[Coffee.]

As Laura said, tampons are not the enemy, but I understand you not wanting to wear one. Personally, I just avoid swimming on my period. Even with a tampon, I'm always afraid I'm gonna leak, but my period isn't as light. But you shouldn't let it get in the way of your fun. If your period is light, you might just be able to get away with it. I've gone swimming while spotting and had nothing happen, I'd just be quick to put on a liner/pad once you get out.