Underwater Defence Group Command

Underwater Defence Group Command  (Sualtı Savunma Grup Komutanlığı) or Underwater Defence (Sualtı Savunma) simply SAS is one of two special operations units of the Turkish Navy (the other being the Su Altı Taarruz).

The missions of the Su Altı Savunma (SAS) include coastal defence operations, such as clearing mines or unexploded torpedoes, and disabling enemy vessels or weapons with underwater operations; as well as counter-terrorism and VIP protection.

The first S.A.S. and S.A.T. units were established in 1963 in the city of Iskenderun, following a joint training program with the US Navy SEALs from San Diego. The original name of the S.A.S. unit was Su Altı Müdafaa (S.A.M.), while the original name of the S.A.T. unit was Su Altı Komando (S.A.K.), and they were bound to the Kurtarma ve Sualtı Komutanlığı (K.S.K.), or Rescue and Underwater Command. In 1974 the S.A.S. and S.A.T. group commands became bound to the Turkish Navy's General Command, and participated in the Turkish military invasion of Cyprus later that year.

The S.A.S. and S.A.T. are based in the Foça Naval Base near İzmir, on the Aegean coast of Turkey.