Dane Cook and Girlfriend Show Serious PDA on Hawaiian Beach

Dane Cook is still gettin' it ... canoodling with his hot, 19-year-old girlfriend on the shores of Hawaii.

The 45-year-old actor/comic revealed last month he was dating Kelsi Taylor. She's in show biz too ... trying to make it big as a singer and an actress.

They've been together for awhile ... it's their second trip to Hawaii. They made the trek last July.

This time around they vacationed with 3 friends on the island of Maui ... arriving in a private jet.

BTW ... Dane's never been hitched before and has no kids. He does, however, have a dog, Chopper, so we're guessing Kelsi must love dogs.