Looking for turtles on Zamami

Hi there! I'm going to be in Okinawa around the middle/end of October. I'm planning a trip to Zamami, and the one thing I'd really like to do there is snorkel and see some turtles. Last trip I went to Tokashiki and snorkeled there, and while it was a wonderful experience, I was unable to see any sea turtles…and I love them so I'd really like a better chance at seeing some this time!

I'm not sure if I should find a tour guide to take me to the best spot to increase my turtle-spotting chances, or if there are just places I can go on my own that would be best. If a tour is better, are there any you recommend? If going on my own is better, any good spots to try? I want to go in better educated this time around, so anyone's expert (or experienced) advice would be so deeply appreciated. Thanks Okinawa sub!