They are similarly wearing the clothing at the beach for religious reasons. I was a Catholic once signed up with a religious order, but didn't go, and years later am non-religious, though I'm not anti-religion generally speaking.
In my day, a long time ago, convents rarely had pools. I've no idea about now.
Just after all that going on with me, nuns in the U.S. changed a lot, usually foregoing habits in their orders, unless they were in the few cloistered orders. It may have been the Immaculate Heart nuns in Los Angeles that started it in the U.S., maybe under Pope John XXIII, but whatever order started it, the changes grew rapidly. Those habit free nuns often worked in "the world" helping people and were dressed as ordinary women, modestly. Whether they went to gyms and swam, or to the ocean and swam, I have no idea.
You're naturally welcome to your opinion that my considering the Imam's noticing the similarites was refreshing was not a good thing.