If you're planning to visit Zamami-jima in Okinawa's Kerama island chain, maybe for the beaches and scenery, there are a couple of ferry options from the main port of Naha. Whichever one you choose, it's an enjoyable journey, if you had good weather like I did (and if the weather's rough, you might want to reconsider your plans!)
The Queen Zamami 3 takes an hour and costs ¥3140 one way, ¥5970 return; the Ferry Zamami takes two hours and costs ¥2120 one way, ¥4030 return. Children are half-price, and there are discounts for groups and the handicapped.
During the crossing, you get a refreshing sea breeze and hypnotic views of the open ocean, then as you enter the Keramas, you glide by scores of little islands and islets, which reminded me of Thailand. Even before you dock at Zamami, you'll be thoroughly relaxed and at ease.
