I was in Ishigaki, Taketomi and Iriomote late December. Probably not a good season to go but we wanted to escape winter. We do not travel luxe so ymmv.

Weather was unseasonably cold (according to locals) that week, around 15C at night, with strong winds. Not the best time for water sports but we managed to go standup paddling at night and it was fun. Clear night, lots of stars. The snorkeling trip got cancelled because of the winds.

Ishigaki the town area near the ferry terminal is small and unremarkable. Went biking around. Was not crowded but strangely, all the yakiniku restaurants needed reservations. You need a car to get around the rest of the island - don’t stick with the town. Little to do or see. The airport is excellent.

Taketomi was very rustic and had a nice beach with the star-shaped sand grains. We biked all round as well.

Iriomote was an hour ferry ride away and has 2 ports. The northern one (Uehara) gets cancelled on pretty often in the winds of December. Iriomote is even more remote with one single road that hugs the coast. Beautiful island, trekking, kayaking etc but very remote in terms of restaurants etc - you need a car although there is a public bus. Managed to see a glimpse of the Iriomote mountain cat while driving at night, so at least lucky sighting. crossed over to Yubu island on ox carts at low tide - that was fun.

I got a sense that people who live there now really are from all over Japan so I heard less of the Okinawan dialect than I was expecting (from the recent morning asa drama on NHK)

All 3 are places I’d go again to escape the city but at the same time I suppose one can also find similar on Honshu too eg I like the Awa region Chiba