If it’s possible and you’re capable to do it, then I think it’s a moral choice.

If it’s a matter of survival, health or inaccess to a variety of food, I don’t think it really is a choice one should have to make on grounds of morality.

Some companies have started selling period panties made for swimming, see if you can find some and maybe she can swim comfortably going forward.

There are other ways to play with water, like running through a water spreader, water balloons, water gun fight. She can do all of these with whatever her protection of choice is currently.

You can make popsicles by putting decarbonated soda or lemonade or juice (I like mine a bit watered down) in the freezer. Mini ones with icecube trays (and tooth picks?) or larger ones in trays bought specifically for the purpose (or home invented).

Staying in shade and having a fan for cooling off also helps, but isn’t as fun. Going for a bike ride down a fairly flat and shaded park or forest trail could be more fun way to get some wind.

Have you tried asking for the option to wear them ahead of time? People tend to be less allowing and less forgiving when you’re trying to be sneaky.

If you’re autistic (or similar) you may even have the right to headphones and other accessibility tools when it’s not a safety hazard. But that means announcing it to the people in charge and communicating your needs and rights beforehand.

Or you can grow your whole hair out to cover your ears, especially if it’s curly it should provide good cover once it’s long enough.

[Not original commenter]

My general tip for these ask-type communities is to put your question and clarification in the post, and put your own answer in a comment.

This way it reads more as a genuine question and not one meant mostly to get their own answer posted.

It also makes it more likely to actually get others answers and not derail the thread, as people tend to respond to what is written in the post instead of giving their own answer if the poster answers it in the post.

So you can still yap away in the comments, and get answers that aren’t just nitpicking your own answer.

Good luck, have fun!