Saint Efstathios Cave is a historical cave dive beneath Antalya's Kaleiçi cliffs, reached from the port side toward Konyaaltı. It combines Byzantine-era history with a cave setting that rewards controlled, guided exploration rather than a wide-open reef pass. Divers come here for the atmosphere as much as the marine life: monk seals, loggerhead turtles, octopus, moray eels, and groupers are all part of the appeal. Plan it as a certified cave dive with a local operator, calm-sea timing, and a short, focused underwater visit.