Celebs Ready for Summer, See Hollywood Try Out Water Sports

It's officially sunny summer time ... and Hollywood is ready to get outside and stay active n' cool with an array of water sports.

Sydney Sweeney's letting the girls get some fun in the sun ... busting out of a brown bikini as she lounges on a jet ski.

Hailey Bieber's saying "SUP" ... paddling around on a stand-up paddle board for a sexy workout in a neon green bikini.

Patrick Schwarzenegger and Abby Champion are going under the sea ... for some couple's snorkeling ... but only after sipping a freshly opened coconut on a boat.

Diplo's going a little more extreme ... with some wakeboarding ... all while chugging a canned beverage. Send it!!!