Asi Koyu is a small bay with a beach and restaurant (with showers)! It’s a convenient stop off for yachts transiting between Marmaris and Gocek/Fethiye Bay that don’t want to detour to Ekincik.
The restaurant has provided a jetty for yachts but the bay is also accessible by road (albeit a rather basic one) so sailors won’t have the beach entirely to themselves during the day.
I’m told the snorkelling is good though I can’t report from personal experience. There is also a mystery I’ve yet to find the answer to; perhaps someone can enlighten me. Asi Koyu translates as Vaccine Bay which seems a rather curious moniker for such a nice spot.