What to pack for overnight beach volleyball tournament?

I would make sure and pack spandex and a sports bra, thats what most people wear.

i've played at the siesta key tournament for the past two years and have spent the past four months playing in the first sand volleyball season for the NCAA so i've gained lots of experience on what you need! collegiate teams are required to wear their school uniforms but considering that you're in a casual tournament, any outfit will be fine. several girls wear just spandex and their sports bra but it doesn't leave the prettiest tan line so others would play in their swimsuits. honestly though, its just personal preference. i personally wore a sports bra and bikini bottoms when we weren't required to wear our uniforms. definitely bring sunglasses and sunscreen like you had mentioned, but also a large towel to sit on will be useful as well as a smaller 'sweat' towel that you can carry around and keep with you alongside your court. trust me, having a sweat towel to wipe your face in between timeouts is super useful! sand socks are also helpful in providing comfort for your feet on very hot sand. other than that are just personal items, such as water, snacks, etc. good luck in your beach tournament!

If no one is there to provide you with basics: Water (lots!) Fruit Salty snack Starch Extra t-shirts sunscreen Sun umbrella if its gonna be real hot Sand socks (if its going to be really hot) A ball Whistle As for clothing, both options you listed are very common on the beach. Some wear swim suits, some wear spandex, some wear running shorts over their swimsuit/spandex. Its really fair game for whatever you want. I find that fitted clothing tends to capture sand.