Alanya's underwater topography shelters more than thirty mapped dive sites within a twelve-kilometer arc of coastline, many clustered around Turtle Island, a limestone outcrop two nautical miles southeast of the harbor. The island's western flank drops to eighteen meters in a series of volcanic shelves colonized by sponge gardens and grouper populations that have rebounded since the 2019 no-take zone designation. Surface temperatures hold at twenty-four degrees Celsius from May through October, reducing thermocline shock and extending bottom time for recreational divers working within no-decompression limits. Scuba diving Alanya price structures reflect the region's shift from single-operator beach dives to consolidated boat-based itineraries. A standard single-tank excursion, departing at 08:30 and returning by 13:00, runs between forty and fifty-five euros per person, inclusive of cylinder, weights, and basic rental gear but excluding wetsuit and dive computer. Double-tank packages—accounting for sixty-two percent of bookings in the 2025 season—add lunch service, typically grilled sea bass or vegetarian meze, and stretch the return window to 16:30. These range from sixty-five to seventy-five euros depending on transfer inclusion and group size. Certification-level variance is minimal; PADI Open Water and SSI equivalents access identical sites, though Advanced certifications unlock the French aircraft wreck at twenty-eight meters off Kargıcak. Turtle Island itself is a geological artifact of the Late Cretaceous tectonic uplift that formed the Taurus range. Its name derives not from loggerhead nesting—rare this far east—but from the profile visible from Cleopatra Beach, which Ottoman mariners charted as Kaplumbağa Adası in sixteenth-century portolans. The dive sites encircling the island favor macro photography: nudibranch aggregations peak in June, and juvenile octopus occupy the rubble fields between twelve and fifteen meters year-round. Visibility averages twenty-two meters in summer, occasionally pushing thirty in September when plankton blooms subside. Operators licensed through the Turkish Underwater Sports Federation maintain a two-to-eight diver-to-guide ratio, stricter than the WRSTC's four-to-one recommendation but mandated under Antalya provincial maritime codes updated in 2023. Most boats are twelve-meter fibreglass gulets with twin diesel engines, aluminum dive ladders, and dedicated rinsing stations. Nitrox fills remain uncommon; only three harbourside compressors are membrane-certified, and surcharges run fifteen euros per tank. The logistical bottleneck is transfer coordination—hotels along the Okurcalar and Avsallar strips lie thirty to forty-five minutes from embarkation points, so morning departures require 07:15 pickups.