The pair got away from Los Angeles to celebrate the birthday boy’s big day on Saturday, making time to relax on the beach — and get cozy underwater.
“Happy birthday babe! Thank you for being you,” the 19 year old wrote alongside a shot of the pair snuggled up together in their bathing suits while partially submerged underwater.
“Love you,” she added.
Richie also went on to share a picture of herself walking on the beach while wearing a black string bikini top with matching bottoms. “Names Buck,” she wrote alongside the image.
Later that evening, Richie shared a photo on her Instagram Story of the pair sharing a kiss on the lips.
While the pair’s vacation was full of romantic moments, Disick also brought along his children.
Documenting his birthday dinner, the proud papa shared a sweet photograph of himself kissing his 3-year-old son Reign, whom he shares with ex-girlfriend Kourtney Kardashian. The exes also share son Mason, 8, and daughter Penelope, 5.
“Me and my mini me,” he captioned the image.
Unlike her sisters Kim Kardashian West, Khloé Kardashian and Kendall Jenner, Kourtney didn’t wish her ex a happy birthday on social media, but she did share a photograph of herself listening to Katherine McPhee’s song “Over It.”
- Want to keep up on the latest from PEOPLE? Sign up for our daily newsletter to get our best stories of the day delivered straight to your inbox.
Richie and Disick have been officially dating since last September after initially sparking romance rumors a year ago. In recent months, the relationship appears to have gotten increasingly serious, with Richie spending plenty of time — and even vacationing — with Disick and Kourtney’s three children.
While a source previously told PEOPLE that Kourtney, 39, still thinks Richie is “too young” for Disick, the couple has Kourtney’s blessing so long as their relationship helps keep him on track.
“Sofia is helping Scott be a better, healthier person,” the source explained. “Kourtney feels confident that Scott and Sofia takes good care of the kids. Scott is a great dad when he has his life together.”
As for Disick? He thinks it’s “kind of flattering” that people care about his love life.
“It’s not like I’m mad about it,” he told PEOPLE in March while hosting a party at Jewel nightclub in Las Vegas. “Everybody’s worried about something. Everybody is worried about other people’s things, so it’s fine.”