austink, I can't tell you that either. I have friends that have used it a number of times and said that they were not stung. And even though they continue to use it, they still hesitate to say that they positively would have been stung without it. They use it more as a better safe than sorry sort of thing. I've never yet heard of anyone that used it that was stung anyway, for whatever that is worth.
You may have noted other comments here regarding getting rinsed off in fresh water immediately and getting your bathing suit all rinsed out very well too. It seems to me then that the Safe Sea should be applied to all parts of your body, even those that will be covered. It is only going to neutralize where it has been applied. That said, what size of sunscreen do you generally take with you? I usually take an 8 to 12 oz bottle of sunscreen and will use it all up with everyday application.
How often are you going to be in the water?
I'd be very surprised if you can buy Safe Sea in Belize. You should buy it at home.