Kas and Kalkan are neighboring but distinct Turkish Mediterranean dive bases. Kas harbor supports day boats to rocky reefs, dramatic walls, historic-looking underwater settings and purpose-sunk artificial reefs. Kalkan has its own dive access from Kalamar Bay, including guided shore entries and compact two-dive morning trips. Dedicated freediving schools operate in Kas, while both towns suit swimming, snorkeling, Lycian walks and beaches. May-June and September-October balance water activities with milder crowds and heat; summer is warmer but busier. Archaeological material, caves and deep military wrecks are not unrestricted recreational attractions. Confirm each permitted dive site with an authorized local guide. Sources: PADI destination overview, PADI Kalkan shop listing, and Life Aquatic Kas.