My son recently went boating with me, and then I realized: I need a normal children's life jacket, not the kind that is sold in supermarkets "for the pool". As a result, I found a good option at
https://gaelixmarineservice.com/safety/foam-lifejackets/ . I ordered several at once, both adult and children's. Foam models are really comfortable: easy to put on, quickly adjustable and not afraid of punctures. Now, when our whole family goes out on the water, I feel calmer. Safety is no joke, especially when it comes to children.