The "Once Upon a Time in Hollywood" actor and Penn were seen getting chummy on a yacht in Italy on Saturday with their much younger girlfriends.
DiCaprio, 44, arrived first with his leading lady, Camila Morrone, who is 22 years old.
Riding up to the yacht on a small boat, the duo looked like they were enjoying each other's company before even getting onboard.
Once on the yacht, they couldn't keep their hands off each other.
Morrone, who's Al Pacino's stepdaughter, was photographed holding the actor from behind and giving him a lovely hug in the sunshine.
When Sean Penn arrived with his 27-year-old girlfriend, Leila George, all bets were off.
The award winning actors looked like old friends as they hugged it out ahead of their big day on the water.
While Leo opted to keep his shirt on, 58-year-old Penn couldn't wait to take his off.
Showing off his hard body, the actor had some fun keeping up with his much younger girlfriend.
The two jumped off the yacht together into the crystal clear water. Based on Penn's form, we're going to guess he was feeling the repercussions today.
Leo and his girlfriend we not as adventurous and opted to stay on the boat and out of the water.
The couple have been away in Italy for quite a while following his Quentin Tarantino movie hitting theaters last month.
Penn was later seen with a cigarette in his mouth and drink in hand.
While their age gap is quiet large, the actor's girlfriends are anything but a fling.
Penn's been dating George since 2016 and Leo has been going strong with Morrone since early last year.