Heather Graham Strips Down to Tiny Black Bikini on Italian Vacation

Heather Graham is in full summer mode on her Italian vacation ... stripping down to a tiny bikini while enjoying the sun and surf in Sardinia.

The "Boogie Nights" actress walked around the beach late last week ... wearing a skimpy black, thong-style bikini and a floppy white sun hat to keep the blinding sun off her face.

It looks like she's trying to keep a low profile in a pair of dark sunglasses ... but, her bod certainly drew eyes -- so, it probably didn't work like a charm.

HG isn't just on the island for pleasure -- though it's hard to tell from the pics ... she actually attended the Filming Italy Sardegna Festival ... taking part in the jury for the short film competition.

While many of the jurors were foreign filmmakers ... Alec Baldwin also served on the panel -- talk about heavy hitters in Sardinia!

Heather's getting a well-deserved break before she gets busy once again ... 'cause she's got multiple projects -- including a "Carrie" show based on the Stephen King novel and movie of the same name -- coming soon.