Brooks Nader Takes Top Off, Exposes Boobs at Beach

Brooks Nader's newest photoshoot is probably more appropriate for Playboy than Sports Illustrated's Swimsuit issue ... 'cause she ditched the bikini for an au naturale look on vacay.

The model ran off to Los Cabos, Mexico for a little Valentine's vacation ... and, she decided to really let loose -- throwing off her top and letting it all hang out.

Check out the pics ... Brooks starts with a bright orange top on while her topless gal pal photographs her -- but, she quickly decides to get as naked as her proverbial dancing partner and frees the nipple for the whole beach to see.

She didn't win the Mirrorball trophy this year ... but, she's certainly brought her own disco balls to the beach -- and, she didn't cover up when she took a phone call at the resort.

Worth noting ... Brooks was spotted with a girlfriend and was lying next to a man in a beach chair -- unclear how well they know each other -- but, her "Dancing with the Stars" partner Gleb Savchenko didn't go on vacation with her.

We caught up with the on-again, off-again couple back in December ... and, they confirmed they were involved -- though they admitted they weren't engaged.

Now, it's unclear what the status of their relationship is ... but, clearly GS didn't get an eyeful -- or handful -- on vacation.