perfect season

A perfect season is a sports season, including any requisite playoff portion, in which a team remains and finishes undefeated and untied. The feat is extremely rare at the professional level of any team sport, and has occurred more commonly at the collegiate and scholastic levels in the United States. A perfect regular season (known by other names outside the United States) is a season ''excluding'' any playoffs, where a team remains undefeated and untied; it is less rare than a complete perfect season but still exceptional.

A perfect season may be part of a multi-season winning streak, or even a streak of perfect seasons.

Exhibition games are generally not counted toward standings, for or against. For example, the 1972 Miami Dolphins (below) lost three of their preseason ("exhibition" games in 1972 NFL vernacular) games but are considered to have had a perfect season.

Perfect season in fantasy sports is defined as follows: The league will declare a franchise to achieve the elite status of a “Perfect Season” when the following criteria have been met during the course of one season:
- The team wins all their head to head regular season matchups and is declared regular season champion.
- The team wins all their playoff matchups and is declared playoff champion.
The feat is extremely rare in high level fantasy sports, and considered almost impossible in fantasy NBA.

Basketball

Basketball leagues outside the NBA tend to be shorter than the NBA's 82-game season, thus making a perfect season more achievable.

Khimik won the 2014–15 Ukrainian Basketball SuperLeague by winning all 30 regular season games, and winning all playoff games, for a 36–0 overall record.

Cricket

County cricket

English first-class county cricket has existed as the top tier of domestic cricket in England since the middle nineteenth century, and until the 1950s it was up to the highest standard of the game. Seasons have varied in length: before the 1880s, they were generally less than ten matches in length and some "first-class" counties played only against one or two different opponents, so that a team winning all its games was not implausible. Between 1887 and 1929, seasons were gradually increased in length to a standard twenty-eight matches for all counties. However, because of the development and popularity of one-day cricket, seasons have been reduced to twenty-four games in 1969 and twenty in 1972, though this was increased by two in 1977 and 1983. With an increase to four days for all games, sixteen or seventeen games have been played since 1993.

Also, because of improvements to pitches via the heavy roller and covering to protect from rain, the proportion of games "drawn" (not finished) has steadily risen since the 1870s.

Since tables of results have been kept in 1864,Wynne-Thomas, Peter; ''The Rigby A-Z of Cricket Records''; pp. 53 to 67. the only team to have competed a true perfect season — winning outright every game — was Yorkshire in 1867 when led by George Freeman's and Tom Emmett's deadly fast bowling on uncovered and unrolled pitches, they won all seven county games.

Since 1868 numerous county teams in longer schedules have finished a season unbeaten, but none have managed to win every single game outright:

American football

National Football League

Since the National Football League began in 1920, only one team has played a perfect season (both regular season and playoffs): the 1972 Miami Dolphins, who won all fourteen of their regular season games and three postseason games, including Super Bowl VII, to finish the season 17–0–0.

The next year the Dolphins extended their winning streak to 18 before losing their second game to the Oakland Raiders on September 23, 1973. It has often been reported that the surviving members of the 1972 Dolphins would, every season, either gather to drink champagne when the final undefeated team earned its first loss of the year, or send a case of champagne to the team who beat this final undefeated team. The head coach of the 1972 Dolphins, Don Shula, denied this in a 2007 interview with ESPN. On August 20, 2013, four decades after their accomplishment, President Barack Obama hosted the 1972 Dolphins noting that they "never got their White House visit".

NFL undefeated seasons (with ties) before 1932

Until the development of a playoff system in the NFL in 1932, there were four teams who completed seasons undefeated, but with one or more tied games: the 1920 Akron Pros, the 1922 Canton Bulldogs, the 1923 Canton Bulldogs, and the 1929 Green Bay Packers. According to the 2012 NFL Record & Fact Book, under NFL practices at the time, from 1920 to 1971 tie games were not included in winning percentage (there was also no overtime to settle ties in the regular season until 1974) so, these four teams were recorded with perfect win percentages of 1.000.

The 1921 Buffalo All-Americans were controversially denied a similar type of near-undefeated season, when they believed that their final game, a 10–7 loss to the Chicago Staleys, was an exhibition game which would not count in the final standings; the NFL records that game as official, and Buffalo's record as 9–1–2.

Other NFL perfect regular seasons

Apart from the 1972 Dolphins, three NFL teams have completed undefeated and untied regular seasons: the 1934 Chicago Bears, the 1942 Chicago Bears, and the 2007 New England Patriots.

In 1934, the Bears played a 13–0–0 regular season and became the first NFL team to complete an undefeated regular season without tied games, but lost the 1934 NFL Championship Game against the New York Giants. Despite losing several players and head coach George Halas to military service in World War II, the 1942 Bears finished 11–0–0 but again lost the NFL Championship Game, this time against the Washington Redskins.

The 2007 Patriots became the first and only team under the 16-game schedule used from 1978 to 2020 to finish the regular season undefeated. The Patriots then won their divisional and conference playoff games, but were upset by the New York Giants in Super Bowl XLII in dramatic fashion, giving them a final record of 18–1.

Pre-NFL era and competing leagues

NFL predecessors such as the Ohio League, New York Pro Football League and Western Pennsylvania Professional Football Circuit had many perfect seasons. In Ohio, the Massillon Tigers (1904, 1905), Akron Indians (1909), Shelby Blues (1911), and Dayton Triangles (1918) all had perfect seasons during this era. In New York, the Buffalo Niagaras went 5–0–0 (6–0–0 including a forfeit) in a league that consisted of teams entirely from the city of Buffalo in 1918. In 1920, the Union Club of Phoenixville, located in eastern Pennsylvania, played in a league mostly consisting of local teams and earned a perfect season, claiming for itself a mythical national championship. In western Pennsylvania, the 1900 and 1901 Homestead Library and Athletic Club teams, as well as the 1903 Franklin Athletic Club, all had perfect seasons.

The caliber of talent was neither as high nor as consistent between teams at the time, the seasons were generally shorter (7 to 11 games), and it was not uncommon for top teams to play all their games at home while lesser teams played all of their games on the road. In 1918, Dayton and Buffalo had the additional advantage of having its strongest competitors suspend operations due to the Spanish flu and the First World War, restrictions that also prevented the two teams from playing each other. Thus, it was much easier to earn a perfect season than it would become in the NFL.

1937 Los Angeles Bulldogs

The Los Angeles Bulldogs were a member of the second American Football League, who joined the league in 1937 after the Cleveland Rams defected to the NFL. Playing a combination of AFL teams and independent franchises (such as the Providence Steam Roller and the Salinas Packers), the team went 16–0, with 8 of those wins coming against AFL teams. The Bulldogs’ dominance is cited as one of the key factors in the AFL's demise, and the next season as an independent with a 10–2–2 record including a 2–1–2 record against NFL teams, several of the team's players were invited to play on the "Pro All Stars" team in the NFL's first Pro All-Star Game in Los Angeles. The Bulldogs are considered to be one of the few independent teams to have ever achieved parity with the NFL.

1948 Cleveland Browns

The Browns were a member of the All-America Football Conference, a professional football league that played from 1946 to 1949. In 1948, the Browns won all fourteen regular season games and the 1948 AAFC championship to post a 15–0–0 record. Cleveland's perfect 1948 season was part of a longer string of 29 straight wins, which stretched from 1947 to 1949 and included both the 1947 and 1948 title games. Overall, the Browns won all four AAFC championship games and were accepted into the NFL when the two leagues merged after the 1949 season.

Near-perfect seasons

Since the NFL expanded to a fourteen-game regular season in 1961 (being expanded twice since then), eleven teams have had regular seasons with one loss and no ties (or better) while failing to achieve a perfect season:

Most of these teams above suffered their only regular-season loss early in the season and, other than the 2007 Patriots (started regular season and playoffs 18–0), only the 1962 Packers (10–0), 1985 Bears (12–0), 2011 Packers (13–0), and 2015 Panthers (14–0) were on track for a perfect season when they lost. Coincidentally, the 1985 Bears’ lone loss came to the Miami Dolphins.

The best start from an NFL team who failed to complete a perfect regular season is shared by two teams: the 2009 Indianapolis Colts, who started 14–0 before losing their final two regular season games to the New York Jets and the Buffalo Bills to finish 14–2, and the 2015 Carolina Panthers, who went 14–0 before losing to the Atlanta Falcons and going on to finish the regular season 15–1. The 2009 Colts, having clinched the top seed in the AFC, sacrificed their chances at a perfect regular season and instead rested their starters the final two games to protect them for the playoffs, on orders from then General Manager Bill Polian. The Colts faced immense criticism from their players, their fans, and the media for letting their chances of a perfect season slip away. The Colts would go on to Super Bowl XLIV but lost to the New Orleans Saints. The 2015 Panthers were not resting their starters at the time of their loss (at the time, the Arizona Cardinals were 13–2 and still had an opportunity to surpass the Panthers for the top seed in the NFC).

Four other teams have started 13–0 before losing in their fourteenth game: the 1998 Denver Broncos, 2005 Indianapolis Colts, 2009 New Orleans Saints and 2011 Green Bay Packers (Of those near-perfect seasons, the 2005 Colts and the 2011 Packers did not win a single playoff game). The 1998 Broncos, 2005 Colts and 2009 Saints lost at least two of their final three games but the Broncos and Saints recovered to win the Super Bowl. The 1953 Cleveland Browns and 1969 Los Angeles Rams started 11–0 in twelve- and fourteen-game seasons respectively; both lost their only playoff game.

Other leagues

The following is a list of teams in minor or alternate leagues that compiled perfect seasons of six games or more, including postseason games, with no ties:

*The Hollywood Bears, a member of the Pacific Coast Professional Football League, went 8–0–0 in 1941.
*The Hollywood Rangers were a member of the American Football League of 1944 (formerly the Northwest War Industries League), a short-lived competitor to the Pacific Coast Professional Football League on the West Coast. In their 1944 season, they went 11–0–0 and defeated the PCPFL champion San Diego Bombers (who had also had a perfect season in their league, going 9–0–0) in a two-game series.
*The Charleston Rockets of the Continental Football League won all 14 games of the league's inaugural season in 1965, going on to defeat the Toronto Rifles in the league's championship.
*The Hartford Knights went 17–0–0 in 1972 as a member of the Seaboard Football League, including a victory over the Chambersburg Cardinals in the league's championship. The Knights, unhappy with the level of competition (many of the Knights games had margins of victory of 40 points or more), quit the league the following year.

In indoor football, the following teams have had perfect seasons:

*The Quad City Steamwheelers went undefeated in the inaugural season of arenafootball2, accruing a record of 19–0–0 including playoffs and an ArenaCup I win.
*The Ohio Valley Greyhounds of the National Indoor Football League accrued a perfect season in 2003.
*The Sioux Falls Storm of United Indoor Football won back-to-back perfect seasons in 2006 and 2007, winning the United Bowl championship both years.
*The Fayetteville Guard won a perfect season in 2007 in the NIFL.
*The Rochester Raiders won a perfect season in 2008 in the Continental Indoor Football League, but withdrew from that league during the playoffs in a dispute.
*The Chicago Slaughter won a perfect season in 2009 in the CIFL.
*The Baltimore Mariners won a perfect season in 2010 in the American Indoor Football Association.
*The Erie Explosion won a perfect season in 2013 in the Continental Indoor Football league, winning all ten regular season games, a semifinal playoff, and the CIFL Championship.

At least twenty-three other semi-professional football teams have had perfect seasons, seven of them being at least 17 games long. The Chambersburg Cardinals won a record 72 straight games between 1977 and 1984.

There have been no perfect seasons (or even perfect regular seasons) in the American Association, World Football League, United States Football League, original XFL, the Arena Football League or the Alliance of American Football, all of which are now defunct. The United Football League has had two perfect regular seasons, but neither qualify for the list: the 2009 Florida Tuskers finished 6–0, but that team lost the subsequent championship game; the 2012 Las Vegas Locomotives had a record of 4–0 when the league abruptly suspended operations halfway through the season. Likewise, the 2020 Houston Roughnecks of the second incarnation of the XFL were undefeated at 5–0 at the time the season was canceled due to the COVID-19 pandemic in the United States.

The 1933 Providence Huskies (possibly a successor to the Providence Steam Roller) played arguably the most perfect season ever recorded by a professional or semi-professional team: a ten-game season in which they won every game and did not concede a single point during any game.

Leagues outside North America

In the 2014 German Football League the Braunschweig Lions compiled a perfect season (12–0 postseason 3–0), losing only in the BIG6 European Football League which is a different competition. They crowned the season with another German Bowl triumph. Similarly in the 2016 German Football League the Schwäbisch Hall Unicorns achieved a perfect regular season with a 14–0 record, similarly their lone defeat came in the BIG6 European Football League which is not considered for league standings. However, unlike Braunschweig before them, Schwäbisch Hall ultimately lost the German Bowl, in this case to Braunschweig. In the 2017 German Football League season, Schwäbisch Hall once more compiled a perfect season (14-0) but this time also won the German Bowl, again against Braunschweig. Interestingly, their opponent in the final had also entered the game with a 14-0 regular season record. Overall the Schwäbisch Hall Unicorns posted five consecutive perfect regular seasons (GFL games only) between 2016 and 2021 (both inclusive) — their only losses in that span coming in German Bowl XXXVIII (2016), German Bowl XLI (2019), and German Bowl XLII (2021).

Association football

Domestic teams

No association football team has ever achieved a perfect season across all competitions entered, but some have achieved a perfect record in their respective domestic league competitions, although that feat itself is rare. The earliest known perfect league season is that of Rangers F.C. of Scotland who, in 1898–99, won all of their 18 Scottish League Division One matches. Other football clubs to have achieved perfect league seasons since then are: Racing Club of Argentina in 1919 (13 wins out of 13), Ferencvárosi of Hungary in 1931–32 (22 wins out of 22), Dresdner SC of Germany in 1942–43 (23), Sunrise Flacq United of Mauritius in 1995–96 (22), and Nacional of Uruguay in 1941 (20). FC Bayern Munich managed a 11-0-0 perfect record en-route to winning the 2019–20 UEFA Champions League, the first team to do so. The competition's format was reformulated in a single elimination match since the quarterfinals due to COVID-19 pandemic in Europe and its following lockdown.

Many teams have achieved an unbeaten domestic season with zero losses, but with several draws.

In women's football, Italian club Juventus become the first to win the Serie A with a perfect record (22-0-0) in the 2020–21 season, an unprecedented feat in Italian men's or women's football history. The following season, FC Barcelona did the same in Spain's Primera División with 30 wins from 30 matches.

FIFA World Cup

The likelihood of a national team in the FIFA World Cup winning all its matches in regulation time to become the champion is much higher than most clubs in their domestic league, as the finals tournament in its current format lasts only seven games. This feat has been achieved three times, by Uruguay in the inaugural 1930 tournament, and by Brazil in 1970 and 2002. This is not counting the qualifying round of the tournament, which lasts over a year and has had a varied format since 1934. Only the Brazilian team of 1970 has won every game in the qualification and final rounds of a single tournament, a total of 13 games. As there was no qualifying phase for the 1930 tournament, Uruguay also won all the games they played to become champions. In 2010, the Netherlands came very close achieving the same feat as Brazil did in 1970. The Netherlands won 8 out of 8 qualifying games and went on to win the next 6 World Cup matches in regulation time only to lose in extra time to Spain in the final, ending with a 14–0–1 record. In 1998 France became the only host nation to win all seven games of the FIFA World Cup and win the tournament. In the quarter-finals, however, they defeated Italy on penalties; wins (and also losses) on penalties are represented as a draw in statistics.

FIFA Women's World Cup

Through 2011, the likelihood of a national team winning all of its matches in the FIFA Women's World Cup was slightly greater than in the men's version. The Women's World Cup began in 1991 with 12 teams and expanded to 16 effective in 1999. Under both structures, the winning team only had to win six games (three in group play and three in the knockout stage) to win the title unbeaten. The tournament expanded to 24 teams in 2015, at which time the number of games that the champion must play increased to seven (the same total as in the men's World Cup).

The 2011 event, won by Japan, was the first in which the champion lost in group play; the other finalist, the United States, had also lost in group play. Each previous team to have won the title — the United States in 1991 and 1999, Norway in 1995, and Germany in 2003 and 2007 — won all of its group stage matches. In fact, only one of these teams, the United States in 1999, had a knockout match go to extra time—specifically the final against China, which ultimately went to a penalty shootout. Germany won all of its matches in the 2007 final tournament without giving up a goal, becoming the first team in either the men's or women's World Cup to accomplish this feat. The United States' third championship team in 2015 had one draw in the group stage; in 2019, the United States won all seven games in regulation, by a combined score of 26–3, en route to their fourth title.

As of the 2019 tournament, four undefeated, untied Women's World Cup champions also went through their qualifying stage without a loss or draw:
* United States, 1991 ( 5 wins, 49 goals for, 0 against)
* Germany, 2003 ( 6 wins, 30 goals for, 1 against)
* Germany, 2007 ( 8 wins, 31 goals for, 3 against)
* United States, 2019 ( 5 wins, 26 goals for, 0 against)

Of the other two teams to win the Women's World Cup without a loss or draw in the finals:
* Norway went through their 1995 qualification campaign with 8 wins, 1 draw and 1 loss.
* The United States automatically qualified for the 1999 edition as hosts.

Australian rules football

Australian Football League (AFL)/Victorian Football League (VFL)

The VFL began in 1897. Based entirely in the state of Victoria, before it expanded through the 1980s, and 1990s to become the top level national league (AFL) in the sport of Australian rules football. The length of a complete season (including finals matches) has typically been between 18 and 26 games. Throughout the history of the league, no team has ever completed a perfect season. One team, in 1929, completed a perfect home-and-away season, finishing with a record of 18–0; the club won the premiership, but did not complete a perfect season after losing the second semi-final against .

South Australian National Football League (SANFL)

The SANFL has existed since 1877 within South Australia, and until the latter part of the twentieth century was of equivalent standard to the VFL. The only perfect season to be completed was by the 1914 Port Adelaide team, known as the "Invincibles". Port won all four of its pre season matches. It finished the minor round with a 12–0 record, before winning both finals to finish with a 14–0 record and a perfect season. They also won the Championship of Australia against VFL premiers Carlton, to extend that record to 15–0. In addition to this the club played a combined team from all the other SAFL clubs and won to extend the record to 16–0. The closest any team got to Port Adelaide was North Adelaide, losing by 21 points in Round 10. This is the only instance in the big three Australian football leagues (VFL/SANFL/WAFL) where a club has gone undefeated in the pre-season, season main and post season.

In 1912, Port Adelaide had a perfect minor round and then beat West Torrens in its semi-final but lost both the final and Grand Final to West Adelaide.

West Australian Football League (WAFL)

The WAFL has existed since 1885 within Western Australia, and until the latter part of the 20th century was of equivalent standard to either the VFL or SANFL. The 1946 East Fremantle team was the first club in senior WAFL football to have managed a perfect season, winning all twenty-one of its games; it is noted that the playing lists of many of its opponents had been seriously depleted by World War II. The only loss for the season came against Victorian club Collingwood in a post season exhibition match. The 2018 Subiaco team was the second team to complete a perfect season, winning all of its 18 games in the minor round before winning both their second-semi-final against South Fremantle and the Grand Final against West Perth.

Victorian Football Association (VFA/VFL)

The Victorian Football League, known until 1996 as the Victorian Football Association, began in 1877 and was Victoria's premier football league until 1897, and has been the second-tier league in the state since. Perfect seasons have been completed on five occasions in VFA/VFL history, but only twice in full-length seasons:
#by North Melbourne during a war-shortened 1915, with a record of 15–0
#by North Melbourne in 1918, which was also shortened by the war, with a record of 12–0;
#by Geelong West in 1972 Division 2, with a record of 20–0
#by Port Melbourne in 2011, with a record of 21–0.
#by the Footscray reserves during a pandemic-shortened 2021, with a record of 10–0

There were also cases of teams going undefeated through the season in the nineteenth century, but none completed perfect seasons because some of their matches were drawn. Of those, could be interpreted as having been perfect in 1879; it had a record of 15–0–1, and the draw came by agreement when a match which Geelong led 1–0 was abandoned due to inclement weather.

Four other teams have completed perfect home-and-away seasons, but subsequently lost finals matches:
# North Melbourne in 1919 won all eighteen home-and-away games before losing to Brunswick in the second-semi-final and Footscray in the Grand Final.
# Coburg in 1927 won all eighteen home-and away games before drawing with Port Melbourne in the second semi final, losing the replay, then winning the Grand Final.
# Coburg in 1945 won all twenty home-and-away games before losing to Williamstown in the second semi-final and being eliminated by Port Melbourne in the preliminary final.
# Williamstown in 1957 won all twenty home-and-away games before losing to Moorabbin in the second semi final, and being eliminated by Port Melbourne in the preliminary final.

Canadian football

A true perfect season (no losses and no ties through the regular season and playoffs) has never been achieved in professional Canadian football. Only one team, the 1948 Calgary Stampeders (in the pre-CFL era), has completed a perfect regular season; more on this can be seen below.

The current Canadian Football League schedule in place since 1986 would require a team to win 20 games (18 regular season, 1 playoff after bye week, and the Grey Cup championship) to post a perfect record; the closest any team has come to such since the CFL's establishment in 1958 are the 1981 Edmonton Eskimos, who went 14–1–1 in the regular season, en route to winning their fourth of five straight Grey Cup titles by winning both their playoff games, and the closest since the institution of the 18-game schedule coming in 1989, also set by the Edmonton Eskimos, by going 16–2 in the regular season, only to be upset by the Saskatchewan Roughriders in the West Final.

1948 Calgary Stampeders

Under head coach Les Lear, the 1948 Calgary Stampeders completed a perfect regular season with a record of 12–0; they had two wins and a tie during the playoffs to finish with a record of 14–0–1, the only undefeated complete season in Canadian pro history. In the Western Interprovincial Football Union championship (a home-and-home aggregate series decided on total points) against the Regina Roughriders, the first leg was tied 4–4, and the Stampeders won the second 21–10, to win the aggregate 25–14. The Stampeders then defeated the Ottawa Rough Riders 12–7 for the 36th Grey Cup.

Despite the Stampeders' title, their achievement was only lightly regarded in the East. At the time, the Eastern and Western unions played separate regular seasons and met only in the Grey Cup. The Western union was openly regarded to be a weaker competition than the East, and Calgary's win (only the third for a Western team up to that time) was dismissed as a fluke.

Handball

In 2020–21 FC Barcelona Handbol had over all championships a perfect season. They won the following domestic championships: Liga ASOBAL with 34 perfect games, the Copa del Rey de Balonmano, Copa ASOBAL and the Supercopa ASOBAL. At the European level they won the 2020–21 EHF Champions League with 20 perfect games. In total they won 61 games out of 61 in 2020–21.

Germany

In 2011–12, German handball champion THW Kiel achieved a perfect season of as many as 34 matches. Additionally, the team also won the national DHB Cup and the international EHF Champions League.

Spain

In the Liga ASOBAL the FC Barcelona Handbol had 4 consecutive perfect seasons from the 2013–14 season to the 2016–17 season.

Croatia

In the Premijer liga the RK Zagreb is unbeaten for 11 years, they won 190 consecutive games, last time they lost against Osijek Motormodul (38:39) on 14.4.2007. In that 190 games they just have one tie with RK Poreč (31:31), after that game they won 178 games in a row and that row is still active.

Lacrosse

In professional lacrosse, the 1993 Buffalo Bandits are the only team to have won a perfect season in the National Lacrosse League. The Bandits won all eight of their regular season games and won the championship in a two-round tournament; the season was the continuation of a multi-season winning streak that dated to the Bandits’ successful run for the previous year's championship.

In Major League Lacrosse, which began play in 2001, the 2013 Denver Outlaws were the first team to complete a perfect regular season, winning all fourteen of their games. After beating the Hamilton Nationals, the Outlaws had a sequence of twenty consecutive regular season wins despite losing the 2012 championship. However, the Outlaws lost in the first round of the playoffs to the Charlotte Hounds, who had only gone 7–7 in the regular season.

Mountain bike

Cross-country

In the 2017 season the Swiss mountain biker Nino Schurter won 6 out of 6 races and additionally at the World Championships he won the gold medal at the single and at the mixed race and the Cape Epic.

Downhill

In the 2016 season the British mountain biker Rachel Atherton won 7 out of 7 races and additionally at the World Championships she won the gold medal.

Netball

Commonwealth Bank Trophy

The Commonwealth Bank Trophy was the main national netball competition in Australia from 1997 to 2007. There were eight teams in a double round robin format and finals.

The Sydney Swifts were the only team to achieve a perfect season, winning all fourteen regular season games and both their finals matches for a record of 16–0.

ANZ Championship

The ANZ Championship, the principal netball competition for Australia and New Zealand was established in 2008 to replace the Commonwealth Bank Trophy. Comprising ten teams (five from Australia and five from New Zealand) there has so far been one perfect season, by the Mission Queensland Firebirds, based in Brisbane, Queensland in 2011. The Firebirds won thirteen regular season games and both their finals matches for a record of 15–0. In 2010, the New South Wales Swifts managed to win all thirteen regular season games, but lost both of their finals matches and ended with a 13–2 for that year.

Rugby league

National Rugby League

The National Rugby League has existed since 1908, being originally known as the New South Wales Rugby League and before the Super League war of 1995 as the Australian Rugby League. In its history, only one team has completed a perfect season: the South Sydney Rabbitohs in 1925, who won all twelve games contested.

Five other teams have gone undefeated but featured at least one drawn match: Balmain (1915), North Sydney ( 1921), Eastern Suburbs (1936 and 1937) and St George ( 1959).

Brisbane Rugby League

The Brisbane Rugby League premiership began in 1909 and continued in varying forms until 1996, after which it was superseded by the Queensland Cup. Between the 1930s and the 1960s it was of comparable standard to the New South Wales Rugby Football League, but subsequently a huge drain of players to Sydney eroded the standard of play. Before World War II seasons were typically no more than twelve games long; however as the competition grew it was expanded to 21 games by 1960. The only BRL teams to manage a perfect season were:

The following team managed an undefeated season but drew one game:

The following teams managed an undefeated home-and-away season, but subsequently lost finals matches:

British Rugby League

Whilst no rugby league team in Britain has completed the perfect season in the top flight, this has been achieved on four occasions in lower divisions, twic in the 2nd division and twice in the 3rd. Hull F.C. achieved this feat in the 1978–79 Season, where they won 26 from 26 games, gaining promotion to the top division for the second time in three seasons. This was also achieved by the Dewsbury Rams in 2009 during their Championship 1 (third division) season where they won all 18 games from a possible 18, winning promotion immediately after being relegated the previous season where they won just two games. Since their 2009 promotion, the Rams have so far stayed in the sports' second division, including two play off finishes. The third occasion came in 2021 when Toulouse Olympique finished the 2021 Championship with a 100% record having won 13 games and awarded a 14th as a walkover. The season was badly affected by postponements and cancellations caused by restrictions imposed under COVID-19 regulations and Toulouse only managed to play 13 games (all away) while all the other teams in the division played 20 to 22 games.

The fourth occasion was in 2022 when