The sea is 'playable' more than 'swimable', ie often quite big 'rolling' waves, so you can play in them. The east side of the bay is more calm with a very gentle shelf, so it doesn't get too deep too quickly. Then there is the reef. Stray further than that and the sea becomes extremely dangerous, not even many surf dudes there. Bozo beach (the opposite end) is entertaining to watch the kite surfers but can have strong undercurrents. I'm not a strong swimmer and I almost got into serious trouble there as the undercurrent took me back out to sea every time a wave came in (apparently, when that happens you should swim parallel to the beach for a while then swim in, better still, don't get into that position!) That area is about level with the Punta Goleta footbridge, which will make sense when you get here.
The beach has been busy today but is getting quiet now as I type this, mainly romantic couples out early or a few stragglers who've not gone for a shower. Between now (6:40pm ish) and 10pm ish it will be quiet with people out for a meal, then it will pick up again at about 10:30pm for a few hours of partying... Obviously, as my wife isn't with me on this trip, I'm always in bed by then, nor do I know if the local girls are friendly or pretty
(honest dear) but they are and they are... so I've been told...
And Rocky's right, with a positive attitude, you'll have a ball, get upset if the water keeps running cold and you may as well have stayed at home!