The Keeping Up with the Kardashians star, 42, shared footage from a beach trip to Montecito, California, that the couple took with Barker's kids - 22-year-old stepdaughter Atiana De La Hoya, 17 year-old son Landon Asher and 15-year-old daughter Alabama Luella.
Kardashian first posted a video of the group running into the water as waves gently crashed against the shore. Barker led the pack, jumping head first into the waves.
Kardashian also included several photos from the getaway, including two of the beach and their loungers, a delicious-looking pasta dish from Italian restaurant Tre Lune, and a beautiful sunset.
"weekend 🤍," she captioned the post. Barker, 45, followed up in the comments section, calling it the "best weekend."
Since making their relationship public in February, the couple has spent plenty of quality time with each other's kids. Earlier this month, they celebrated Memorial Day with two of Kardashian's three kids, daughter Penelope Scotland, 8½, and son Reign Aston, 6.
In her Memorial Day Instagram post, Kardashian shared photos and videos of pool time and a giant inflatable water slide enjoyed by the kids and Barker.
The Poosh founder also posted a bikini selfie, as well as videos of herself and Barker rolling around on a grassy field. "happy weekend," Kardashian captioned the post.
Never miss a story - sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.
Since then, their romance has continued to heat up. From Barker tattooing Kardashian's first name on his chest to packing on the PDA during a romantic getaway in Utah, the pair haven't shied away from showering one another with affection.
In May, Barker got a tattoo of the phrase "I love you" written in Kardashian's handwriting. The design was debuted on Kardashian's Instagram.
A source previously told PEOPLE that Barker "often spoils" Kardashian.
"Kourtney still seems very happy with Travis. He is very into her. He constantly gives her compliments and attention. You can tell he is thrilled to be dating her," the source said. "Kourtney is soaking it all up and enjoying life."