Delfin may refer to one of the following.

• (Translated as "Dolphin" from Russian)
  • The Russian submarine Delfin
  • The KGB OSNAZ organization Delfin, a combat diver group established by the KGB which remains an enigma today, It was known to be used as an "incursion" type special forces group similar to the British SBS or United States Navy SEALS. Unknown if they still exist or were incorporated into other KGB or FSB OSNAZ units.