How to spend our time in Okinawa

Most of the major cultural sites are located around Naha in the southern part of the island. Since you only have four days total, sightsee around Naha and book a one-day dive trip to the Kerama Islands (located about 60 minutes away by boat). If you don't snorkel/dive, you can also just take the ferry to these islands and just enjoy the beach there. I guarantee the beach is much more beautiful than in Naha.