I went to Ölüdeniz beach in September while staying at one of the nearby casual hotels. It's a lovely pebble beach where you can rent a sun lounger and umbrella for 200 lira (just choose an available one and a vendor with a card machine will come to you for payment). You can also order a drink from one of the bars by the beach, take a dip in the pleasant water, or buy roasted corn from the young boys who occasionally walk along the beach. The beach is generally well-maintained, although you may find bottle caps and cigarette butts among the pebbles in some areas.
There are various activities available, such as snorkeling, boat trips, and kayaking. Different vendors offer these experiences, so it's best to ask around and negotiate the best deal for yourself.
The bars and clubs along the beach play loud music late into the night, resulting in competing sounds. During my visit, the crowd consisted of 60% Turkish tourists and 40% British and other European tourists. The presence of Europeans is evident in the food, prices, and nearby entertainment options. While there are two good restaurants serving Turkish cuisine, the rest try to cater to the masses with burgers, overcooked pasta, and steak. Many things are advertised in foreign currency, but you can get a better deal if you pay in Turkish lira.
Despite these quirks, I had a great experience at Ölüdeniz. I never felt bothered, and the staff at local establishments were always polite and helpful. The surrounding mountains and paragliders dotting the sky added to the beautiful ambiance.