Aharen on Tokashiki is a beautiful spot. We ventured out on a beautiful calm morning, and after some practice rows, headed on a sea kayak to the rocky inlets nearby. Little did we know there were beautiful grottoes ahead of us, and one by one, we managed to go inside the narrow openings, and what a delightful adventure it was. Next we went to a remote island uninhabited and with no sign of human life, except for a statue of two rock singers, barely visible from the shore. We proceeded to climb a steep hill where we could draw breath, relax and appreciate how aquamarine blue and turquoise green the clear waters are, with a short lesson from the guide about the geology of the area.http://en.japantravel.com/view/aharen-island-s-trip-adventures
There are two ferry services to Tokashiki Island. The larger car and passenger Ferry Kerama takes 70 minutes, while the smaller Marine Liner ferry takes 35 minutes. You do pay a premium for speed; however the boat you select is more likely to be based on your departure time, as there are only three services a day between the two services. You can call the port at 868-7541 for boat times. If you are going on a day trip, you should board the morning fast ferry, allowing you enough time to see the sights and take a guided snorkeling tour at Aharen before boarding the afternoon’s slow or fast ferry back. However, I suggest that an overnight trip is a better way to slow down to the pleasures of island time. Watching the moon rise over the still, mirror-like waters at Aharen Beach is particularly relaxing. http://en.japantravel.com/view/tokashiki-island-ferry
Victoria, I lived in Okinawa for three years (in Uruma) and there is a surprising amount of things to see in the northern part of the island but the transportation can be tricky. If you are comfortable with it, a rental car is your best option. My suggestion would be to head to the Yomitan Peninsula, halfway up the main island on the west side. You have the Ryukyu Village (Ryukyu Mura), Yachimun no Sato pottery, Zakimi castle ruins, beautiful coastline, a sugar came factory and tons of little cafes tucked away on the smaller roads. If I remember, there IS a bus that rings the peninsula but I don't know the schedule.