I tried this for the first time today. My period was very heavy, so I still wore a tampon. Usually even with a tampon, my period leaks through to my towel when I sit down after a swim. But today, I did an hour swim & sat on the lounge chairs for a while and experienced no leaks! It’s really great for peace of mind. I’d be confident to use it alone with no tampon during light flow days. If you’re training and swimming fast, I would recommend a rash shirt on top, since the chest part can fill up with water and pull the suit down if swimming at high intensity. For moderate or slow laps this is not a problem, and it works fine. Overall, I love the swimsuit and I’m happy to have it! I forgot to mention it also looks really good!