Leonardo DiCaprio and Vittoria Ceretti Tan on Yacht in Cannes

Leonardo DiCaprio‘s keeping summer hot over in France … showing off his beach bod during a yacht trip — and, his girlfriend got the topless memo too.

The actor jumped into the Mediterranean during his sojourn to Cannes … splashing around in the cool, blue water before working on his tan on the ship’s massive deck.

BTW … Leo’s rockin’ a man-bun in these pics — unclear if it’s for a role or just a style choice, but either way, Leo’s definitely pulling it off.

The two weren’t just alone on a romantic vacay BTW … they were joined on the yacht by a group of friends — though, we’re sure the ship’s big enough for everyone to get a little alone time.

Leo and Vittoria are reaching a serious couple milestone … with outlets first linking the two last August — so, they’re right around the big one-year mark.

We’ve seen them sight-seeing in exotic locales, and there was even speculation the two were engaged floating around in March — though that ultimately proved not to be the case.

Good to see Leo’s back in the ocean, too … remember, just a few weeks ago DiCaprio suffered a jellyfish sting — and, he needed medical attention on his A-list ass!