S34 may refer to:

Aviation

* Blériot-SPAD S.34, a French biplane * Plains Airport, in Sanders County, Montana, United States * Sikorsky S-34, an American sesquiplane * Skyfly S-34 Skystar, a Swiss ultralight

Naval vessels

* * , a torpedo boat of the Imperial German Navy * * , a submarine of the United States Navy

* County Route S34 (California) * Sulfur-34, an isotope of sulfur {{Letter-NumberCombDisambig