In Akyaka, between the
town beach and the
Azmak River, you can find excursion boats that depart for one-day sea tours. They usually start in the morning and last until the evening: on average, boats go out to sea around 10:00 and return to port around 17:30–18:00, depending on the route and company.
The classic route includes stops at the most beautiful spots in the Gökova bay — primarily the
Cleopatra Island (Sedir) and turquoise coves towards Marmaris. The tour usually has several swimming stops: the boat enters small bays with clear water, where you can swim, sunbathe on the deck, and have lunch on board. 
The schedule and program content depend on the specific company, so it's best to take a walk along the promenade the day before, look at the boats, and clarify the details.