ear plugs or ear band for swimming - any recommendations?

[Fi from West Dulwich]

I am looking for some ear plugs or an ear band to stop water in ears whilst swimming, for my 16 month old little boy who tends to pull off sunhats and sunglasses. Suspect such items will meet with similar treatment but worth a shot. Does anyone have any recommendations for particular products that fit well and don't get hurled off by toddlers? Thank you in advance for any posts.