Heidi Klum Splashes Around Topless in Ocean with Husband Tom Kaulitz

Heidi Klum's recent beach trip will have admirers feeling as giddy as kids on Christmas morning ... because she unwrapped her pair of presents while swimming.

The model went for a dip off the coast of St. Barts with her husband Tom Kaulitz and their friends ... and, unsurprisingly, she decided to leave her brown bikini top on the beach while they splashed around as a group.

Check out the pics ... Heidi's hanging all over Tom in the water -- pressing her bare chest into his back in several pics while covering her face with a white cap and sunglasses.

When HK hopped out of the water, we got a full view of her chest ... and, while St. Bart's is a tropical locale, it seems there's still a winter chill in the area -- if you catch our drift.

BTW ... it's not like Heidi and Tom were floating around in a secluded cove together. They sat in the water with a pair of friends -- no modesty here.

Of course, Heidi's regularly stripped off her top and let it all hang out ... remember, the star posed a clip where she tanned sans bikini top just a few weeks ago.

Heidi's so used to dropping the top she once admitted her kids felt the need to remind her to throw on some clothes when their friends came over to the house ... though we doubt they'd mind much!