Onna at lower low tide

Onna is accessible via the 58 or the expressway, exiting at Yaka and crossing the island.
From the 58, there are various places to turn to approach the water and find a spot to park. If you turn at the elementary school, you go down a small road and then go right into a dirt opening, follow that around, get as close to the water as possible, and park. There is a cute beach here. We prefer to turn at Manzamo, take a left before entering the tourist trap, then take a right to get to the straight road parallelling the coast. You can park here and find a trail that heads down to the water. This puts you on the beach near the cave pools. You can also drive further into Manzamo and turn down a tiny unmarked street and follow this downhill. This takes you to a grassy area with a picnic table and the toilet bowl dive site entry.
Onna is a sweet spot to spend a sunny spring day, especially at lowest low tide. Check beforehand at the Tide Toya website: http://www.mobilegeographics.com:81/locations/6543.html
At super low tide, you can walk almost the whole length of this coastline over the exposed shelf. Some live coral is exposed, so you have to be careful to avoid it. There are also plenty of sea urchins, making correct foot placement even more essential. This is not a walk for children. But the tidepools are great along here. There are lots of Japanese people out quite far collecting shellfish or whatever.
This little adventure should be combined with sustenance at a local cafe. Our favourite is Cafe Masaho, which is just south of the Manzamo turnoff on the 58 (west side), and by a restaurant with a pig sign. We have reviewed them elsewhere on this site (open at noon). They do plate lunch for 1000-1200Y - they speak minimal English so just point and shoot. All the food is delicious and healthful. One of the sets is a pasta dish.
Afterwards, head to the Onna Resort public beach, which is just north of the Onna fishing port. There are a couple places to enter from the 58 - one at the fishing port, then you turn right and get to the parking lot, and one a little further north that heads more directly into the parking lot. The beach is behind a sporting field and school. There are public toilets, free picnic areas, vending machines, a snack bar, and a lifeguard. During our visit they were not charging admission or parking. To the south is a great view of the cliffs at Manzamo, and to the north is the ANA Intercontinental resort. They have various boats doing touristy things. There is a swimming area perfect for kiddos. We got some drinks at the local Coco (there is also a Family Mart) and spent a leisurely couple hours at a covered picnic table reading our books. Bliss. The beach does have a loudspeaker system playing J-pop, sol you do have to tune this out, but otherwise it is a great spot.