Public Nudity/your entire bikini
Like they say, go big or go home, and you are most certainly not going home yet.
You check yourself over while still underwater. Your bikini was only hanging on by a prayer at this point, your nipples just starting to peer out from the top while your bottoms have slid down to the widest part of your hips, no doubt leaving part of your ass exposed in the back.
One more jump, that ought to do it.
Breaking the surface you take a moment to blink the chlorine from your eyes before swimming back to the ladder a third time. This time the stares linger noticeably longer than before, making you wonder if anyone is actually hoping for a wardrobe malfunction.
Reaching your diving spot you pause to take a deep breath, anticipation welling up inside you. You make this jump then there's no going back. But, that's the whole reason you're here now, isn't it? Without wasting another second you leap into the water a gracefully as ever, heart skipping a beat as you feel your bikini bottoms fly off your legs in an instant, followed immediately by your top freeing itself from your chest and chasing after them. Just to make sure you look back and watch as the two white garments float towards the surface.
You come up for air a moment later, both to refill your lungs and to try and keep calm. Finally, after so long of daydreaming one of your fantasies has finally come true. You're naked in the public pool! And surrounded by your friends and neighbors too! You're certain that if you weren't treading water right now then there would be rivers running down your trembling legs.
Pushing your hair from your face you try to act normal and not start grinning like an idiot. Now that you've ditched your bikini you try to think of what to do next. The most obvious answer would be to go find someone you know and hang with them, waiting to see if and when they'll notice you're only wearing your birthday suit, but what of your bikini itself? You could hide it so nobody tries to return it and ruin your fun, hide it so you can stealthily redress if you want to take a sneakier route, or maybe even keep an eye on it to see who finds it and have some fun with them.
Decisions, decisions...