Never been anywhere near there, but most places that are "tourist spots" are usually pretty tolerant of whatever you choose to wear. Of course you may have zero company amongst the locals, but as long as you are spending money, you will likely be ok. I would recommend starting gradually, with the most conservative thong you own, setting up away from others (if possible), and not walking the beach without a coverup. If all seems ok after a few days, you can relax the above rules.

I went to Africa and pretty much did the trip you're describing. I started with a tour group in Nairobi and we went to Tanzania and then to Zanzibar. I would suggest leaving the thong at home. I'd suggest leaving the bikini at home too. The African people are a very modest people. When I was on the beach in Zanzibar there were even women in Burkinis (burkas that cover the body). When we went to towns our guide suggested that women not wear short shorts. There were two Dutch women in our tour group that I think that's all they packed. The got very disgusted looks from the locals. I wore board shorts on the beach. I wouldn't have considered any thing else otherwise I would have insulted the local people. I say respect the place and people where you are at. Africa, no thongs.. St. Martin...yes!

I was looking at staying at the Royal Zanzibar beach resort. On Trip Advisor there are men wearing speedos and women in bikinis. So I should be ok in a rio swim suit. Thongs we shall see.......