S12 may refer to:
Aviation Albany Municipal Airport (Oregon), in Linn County, Oregon, United States Letov Š-12, a Czechoslovak prototype fighter aircraft Rans S-12 Airaile, an American civil utility aircraft SABCA S.XII, a Belgian passenger aircraft SIAI S.12, an Italian flying-boat Sikorsky S-12, a Russian trainer aircraft SPAD S.XII, a French biplane fighter Spencer S-12 Air Car, an American amphibious aircraft Stemme S12, a German motor glider
Rail and transit
Lines S12 (Rhine-Ruhr S-Bahn), Germany S12 (St. Gallen S-Bahn), Switzerland S12 (ZVV), Zürich, Switzerland Line S12 (Milan suburban railway service), Italy
Locomotives Baldwin S-12, a diesel-electric locomotive Sri Lanka Railways S12, a diesel multiple unit
Stations Asari Station (Hokkaido), in Otaru, Hokkaido, Japan Bang Wa station, in Bangkok, Thailand Iyo-Nagahama Station, in Ōzu, Ehime Prefecture, Japan Kikukawa Station, in Sumida, Tokyo, Japan Mizuho Kuyakusho Station, in Mizuho-ku, Nagoya, Aichi Prefecture, Japan Myōdani Station, in Suma-ku, Kobe, Hyōgo Prefecture, Japan
Roads Airport Expressway (Beijing), China Shanghai–Jiaxing–Huzhou Expressway, China S12 highway (Georgia) Expressway S12 (Poland) County Route S12 (California), United States
Vessels , in service 1963–1972 , in service 1972–1993 , an armed yacht of the Royal Canadian Navy , a submarine of the Royal Navy , a submarine of the United States Navy
Other uses S12 (classification), a disability swimming classification 40S ribosomal protein S12 British NVC community S12, a swamps and tall-herb fens community in the British National Vegetation Classification system Lenovo IdeaPad S12, a laptop Nissan Silvia (S12), a sports car S12: Do not keep the container sealed, a safety phrase Saiga-12, a Russian semi-automatic shotgun S12, a postcode district in Sheffield, England