The only line I have used in Stream2sea. One of my kayak buddies introduced me to it. He said be sure to buy a lotion or cream, because spray products easily transfer to the sand, and enter the environment that way.
It is mineral based, so a little goes a very long way. It is hard to rub in, but lasts app 80 minutes. I have only found spf 30, but there might be other options.
This line was developed by a diver, and avoids ingredients that have know toxicity to marine life.