We cannot pretend to have extensive knowledge of the southern coast, but after two day trips here are our thoughts from west to east:
Nashiro beach, ItomanThere is a signpost off the 331/3 leading to a gated entrance, which claims that admission is 500Y pp. We went on an overgrown side road and parked at its terminus (which is not far from the Kyan fishing port). The beach is not particularly attractive. Its main selling point is it is lined with pine trees. However, there is too much nutrient in the water resulting in a dramatic algae bloom. The facilities are past-their-prime concrete structures reminiscent of an abandoned boy scout camp. The beach is on the flightpath to Naha International airport, which may be a good or bad thing depending on your perspective.
Kyan village was remarkable for the fact that the residents looked away as soon as they saw us, perhaps not that excited about gaijin driving through town. A signposted road leads to the Gushikami castle ruins. There are just a few limestone walls left, but the view over Cape Kyan is nice and there is a sense of tranquility as this site is not on the way to anywhere.
There is a memorial park on the coast east of Kyan. It is hard to understand the point of the park. There is a parking lot, a black stone memorial at the top of the hill, and closed-off roads/trails.
Further along the 331 is the Peace Memorial Park, which is worth one visit while in Okinawa. The memorial wall with the names of WW2 victims is dramatic, the museum is interesting (and an air-conditioned respite on a summer day), and the view tower is impressive.
Continuing on the 331 you can turn off where the 507 meets the 331 and make your way to the Gushikami beach picnic grounds nature walk. Apparently, if you spot the huge Gushikawa gym you can turn there and get to the coast, or try one of the roads heading into town (we took the one by a do-it-yourself store with a blue banner, also marked by a fake wood sign with the kanji for entrance on it). The eastern end of the beach is the most dramatic, with huge rock formations and black rock tide pools, but the air is heavy with the stench of feces (not sure if it is a nearby animal pen or the sewage treatment plant down the road). As you walk west, the smell dissipates and you find an abandoned beach hut and concreted ocean swimming pools. You wouldn't want to swim here now though, the water has quite a bit of algae content.
Next along is the Odo coast. You drive down the hill, through farmland, and then park on a dirt road alongside the beach. The beach is fairly narrow, there is a little shade up against the scrub, and as I remember at the east end is an area that rents water play gear. Not particularly appealing, but OK.
O-jima juts out from the coast shortly thereafter. It is a fairly depressing ex-fishing village now renown for its tempura stalls in season. There is an unattractive beach on the southern side of the island.
For my time and money, the area around Nibaru/Miibaru beach is the nicest on this side of the island. The most popular section has paid parking, concessions, water rides, etc. But this can be avoiding by staying east or west, parking along a side road, and walking onto a more pleasant section of the beach. There are nice rock formations in the water, cliffs behind the sand in some places, and clear water decent for snorkeling. Not much shade, but pretty turquoise water.
Continuing east you reach the turnoff for Cafe Curcuma (the 86) which also leads to a lookout over the northern side of the peninsula and a popular hang gliding area.
Further on the 331, you reach the turnoff for Seta Utaki, a series of rock formations considered holy to the Ryukyuans, somewhat interesting but not earth shattering (small admission fee something like 300Y)
Azama SanSan beach is next up - a man-made beach with entirely too much infrastructure and an inflated parking fee. We read that from here or nearby one can get ferries out to Komaka/Kudaka islands which boast fine snorkeling, but we have not yet done this.
Traveling through this town there is a turn off to the right towards a restaurant overlooking the water. The restaurant has several small concrete pools below it of unclear purpose - possibly fish pens, possible sewage treatment (but no smell). The place was packed with Japanese people at lunch. They did reasonably priced but not especially tasty lunch sets.
Along the whole coast there are parks and overlooks, and I'm sure an array of cute soba shops and cafes. There are also amazingly extravagant fishing ports every couple of kilometers, most of which appear to be barely used, with boats lying idle and fishing nets piled up it the grass being eating by weeds. The farmers seem to be doing better than the fisherman, but you sense this is an area in transition.
