Kas is one of the main scuba diving centres in Turkey and there are over 50 submerged wrecks, one a Douglas DC3, which have created artificial reefs and tourist diving spots.
The most popular excusion from Kas is to the Sunken Lycian city of Selimne near Kekova. Columns, staircases and details of buildings are clearly visible as you pass over on clear waters. Kaleköy, another site that can reached by boat has a castle offering great views.
Other popular activities are trekking the nearby Lycian Way (a 7 day hike but you can just walk a day section) where Lycian Tombs are visible. There is also sea kayaking in Kekova and canyoning in Kibris Canyon.
Nearby ancient sites worthy of a visit are Patara with its hillside theatre and site located on Patara Beach. Xanthos, Komba, Nisa and Kandyba are other sites where visitors can enjoy ancient history coupled with lovely surroundings.