Most of my sports watches (and by that I mean watches with steel or rubber bracelet) are waterproof to swim with.
They were not always like that as assembly is a questionable science in China ...
So I swim with B+R, PP, AP, Hublot, Rolex, Ebel, etc. Also Chronos, although I have yet to use the chrono under water.
Some do not let themselves be waterproof due to construction. Cartier Seatimer Pasha, Porche World Timer, VC Overseas (Arabic numerals) are examples.