Of course, as a Japanese hawaii, there are a lot of beaches in Okinawa.
During our trip to Okinawa, I could taste the Okinawan sea, rightly deemed as very pleasant. Beaches are very clean and the sun beats down: as the archipelago is close to the tropics, you should buy a sunblock.
The first coast we visited is located south of the main island, a few kilometers from Naha. A bus can take you from the capital in half an hour, for a few hundred yen. Arrived in late afternoon (around 5PM), we were virtually alone on the beach. The sun was beginning to decline but the water temperature was still pleasant, which allowed us to bathe in a much appreciated quiet. The scenery was absolutely beautiful: this small beach mixes big rocks, small caves and a dock to tie up small fishing boats. Quite a heavenly panorama!
But if you wish to spend an entire day at the beach, I definitely recommend a stop on one of the many islands off Okinawa. We chose Zamami-jima ('jima' means 'island') for its beauty and easy access from Naha, and we were not disappointed. The island is accessible by ferry. We chose to spend the whole day there, that is to say to go with the first ferry and leave with the last in the afternoon. The trip is really worth it: enjoying breakfast on the deck of the boat and navigating through virgin islands is beautiful.
Once you're on Zamami, one can really take the measure of this Eden on Earth. After docking, a 20-minute stroll to Furuzamami beach sets the tone: the nature is lush with beautiful landscapes, and very calm (the island is inhabited only by a few hundred people). And then we arrive at the beach: a kind of huge sandy cove, with clear water filled with coral. In the center, facilities allow to overhang the breathtaking views, a refreshment in hand. The buildings are very respectful of nature since everything is made of wood, and it's very quiet all along the beach. After resting, we chose to rent fins and snorkels to dive among beautiful coral.
How to get to Zamami
By boat -- 1h (normal) or 2h (express) ferry ride from Naha
Location unreachable with the JR Pass
Get there with a rental car
Find a flight to Okinawa Naha
Roundtrip adult ferry ticket from ¥4,030 / ~US$ 36.60 (all fares on the official website)
Get your Japanese Yens free of charge
Ferries usually from 9am to 5pm (full schedule)
How long / when to visit
Allow half a day to a whole day
It is also possible to stay in a ryokan on the island