Looks like a romantic vacay, but the kids are in tow! Scott Disick and Sofia Richie brought along the Lord's three kids to St. Barth in celebration of Disick's 35th birthday. We're guessing Sofia gifted her man with the trip, putting the entire crew on a private jet and renting the most expensive villa on the island, likely on Lionel Richie's dime. Hot teenage girlfriend and super-luxe trips for free -- sounds like a good deal for Scott!

The pair frolicked on the beach with Mason, Penelope, and Reign -- well mostly nanny Sofia frolicked ... Scott spent most of his time maxing and relaxing on the sand, watching his thong-wearing underage girlfriend take care of his kids. Hey, who wouldn't do that if they had the chance?!

A happy, happy birthday to you, Scott!