I’m going to recommend a seriously good suncream.
It’s called Lemonoil (carrot sun milk) and is manufactured in Spain. Don’t be put off by the name - it isn’t some sort of complementary therapy; the name probably just sounds exotic to Spaniards.
I first came across it in Portugal but I’ve seen it in Cornwall where surfers use it. I think that maybe Spanish suncream regulations are more stringent than UK ones. Certainly when it says water resistant on the bottle it means it. I used it when snorkelling in Tobago (15 degrees above the equator). I used it again when swimming in Kenya (actually on the equator).
It isn’t a substitute for sensible sun behaviour but it really is the best stuff I’ve come across. An added advantage is that it feels nice and soaks in well without feeling greasy.
I obtain it from www.colvininternational.com
Its worth checking out.
Best wishes,
Sue