Originally Posted by
evergrn
I also looked into Ishigaki/Miyako Island, but it was going to cost too much.
The cheapest transport (slower ferry) to/ Zamami Island from Naha will cost 12,000yen return for the whole family. Kind of a lot for a day trip, but I'll definitely keep that in mind and may give it a go depending on the weather, any further feedback on the main island beaches, etc.
You must really get on well with your father-in-law (correct?) to plan a trip like that. That's really great.
Don't forget Tokashiki Island is 9,460 for two adults and two kids and the slower ferry is only 70 minutes.
I'd suggest that for your first Kerama Islands day trip.
If you really like it, you can contemplate slumming it overnight in accommodation in Zamami or Akajima on a future trip. Alternatively, there's lodging on Tokashikijima itself which is a little more upscale, you could resort to that and go to Zamami for a day trip from there.
I flirted with the idea of going to the onsen resort on Kume jima. But only for a moment. The call of Zamami is just irresistible. Have you looked at Kume Island? Might suit your needs (although I'd keep a close eye on the wave forecasts beforehand - the journey there could be something to enjoy or endure)