Coachella Day 1 got the whole crowd rockin' ... while a few celebs flaunted their rock hard abs!

It's hot out in the California desert, and several stars decided to strip down ... like Teyana Taylor who wore a tiny yellow crop top with a pair of low rise leather pants.

Olandria was busting out of a brown bra-top ... which matched her barely-there miniskirt. Meanwhile, Katseye's Daniela Avanzini wore a sparkling maroon bra that certainly drew some eyes.

Other stars going suns out, tums out ... Kendall Jenner, Amelia Gray Hamlin, Rachel Zoe, Lexi Wood and many more!

Day 2 is already in full swing ... and, we expect many more stars to strip down over the weekend -- so stay tuned!