A scout cruiser was a type of warship of the early 20th century, which were smaller, faster, more lightly armed and armoured than

protected cruiser Protected cruisers, a type of cruiser of the late 19th century, took their name from the armored deck, which protected vital machine-spaces from fragments released by explosive shells. Protected cruisers notably lacked a belt of armour alon ...

s or

light cruiser A light cruiser is a type of small or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck. Prior to thi ...

s, but larger than contemporary

destroyer In naval terminology, a destroyer is a fast, maneuverable, long-endurance warship intended to escort larger vessels in a fleet, convoy, or carrier battle group and defend them against a wide range of general threats. They were conceived i ...

s. Intended for fleet scouting duties and acting as a

flotilla leader A flotilla leader was a warship of late 19th century and early 20th century navies suitable for commanding a flotilla of destroyers or other small warships, typically a small cruiser or a large destroyer (known as a destroyer leader). The floti ...

, a scout cruiser was typically armed with six to ten destroyer-type guns of 3-inch (76 mm) to 4.7-inch (120 mm)

calibre In guns, particularly firearms, but not artillery, where a different definition may apply, caliber (or calibre; sometimes abbreviated as "cal") is the specified nominal internal diameter of the gun barrel bore – regardless of how or wher ...

, plus two to four

torpedo tube A torpedo tube is a cylindrical device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units (also referred to as torpedo launchers) installed aboa ...

s. The British were the first to operate scout cruisers, when the

Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...

acquired 15 ships divided into two distinct groups - the eight vessels all ordered under the 1903 Programme, and the seven later, heavier-armed vessels ordered under the 1907–1910 Programmes. All these ships served in

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

, when the advent of better machinery and larger, faster destroyers and light cruisers had already made them obsolete. The other major operator of scout cruisers was the

Kingdom of Italy The Kingdom of Italy (, ) was a unitary state that existed from 17 March 1861, when Victor Emmanuel II of Kingdom of Sardinia, Sardinia was proclamation of the Kingdom of Italy, proclaimed King of Italy, until 10 June 1946, when the monarchy wa ...

. With no conventional protected cruisers or light cruisers planned between 1900 and 1928, the

Italian Royal Navy The , ) (RM) or Royal Italian Navy was the navy of the Kingdom of Italy () from 1861 to 1946. In 1946, with the birth of the Italian Republic (''Repubblica Italiana''), the changed its name to ''Marina Militare'' ("Military Navy"). Origins ...

() instead operated a number of scout cruisers ('' esploratori'') from 1912 onwards. Ranging in size from enlarged destroyers to substantial, light cruiser-like ships, these ''esploratori'' were also given secondary capabilities as fast

minelayer A minelayer is any warship, submarine, military aircraft or land vehicle deploying explosive mines. Since World War I the term "minelayer" refers specifically to a naval ship used for deploying naval mines. "Mine planting" was the term for ins ...

s. Later ''esploratori'', such as the , carried extremely heavy armament for their modest size, capable of outgunning any destroyer of the early 1920s. However, by 1938 the surviving ''esploratori'' were re-rated as destroyers.

Scout cruiser designs

Austro-Hungarian Navy

* *

Brazilian Navy

Kriegsmarine

* Spähkreuzer – Translates to 'scout cruiser' in English; developed from late 1930s Zerstörer 1938A/Ac large ocean-going destroyer design concept intended for oceanic escort.

Peruvian Navy

Regia Marina

''Note: this list includes all vessels rated as scouts (esploratori) by Italy.'' * – protected cruisers, rated as ''esploratori'' from 1914 to 1921 * * * ''Alessandro Poerio'' class - included * * * * - originally classified ''esploratori oceanici'' (ocean scouts), then re-rated light cruisers

Romanian Navy

Royal Navy

* * * * * * *

United States Navy

* ** – later re-classified as light cruisers (CL) ** The first three ships were also designated "scout cruisers" (CS) when ordered, but in 1920, before any were launched, the Navy revised its classification system and they - and the ''Chester''s - became light cruisers (CL).