The rocker's new stepchildren shared a heartfelt message for the special occasion.
The Blink-182 drummer took to his Instagram Story to share some of the heartfelt cards he got from his new stepchildren. Specifically, he posted pics of the two sweet cards he got from Penelope, 9, and Reign, 7, who new wife Kourtney Kardashian shares with her ex, Scott Disick -- along with 12-year-old son Mason.
The first card, from Reign, was written in his handwriting and expressed, "Dear Travis, happy Fathers Day," and featured a stick figure drawing of two people holding hands.
He also shared a sweet card written by Penelope that complimented both his drumming skills and how much joy he brings her mom.
"You are so so nice and kind you are so amazing you are the beast. You are the beast drummer ever. You make my mom happy!" the card shared. "Happy fathers DAY. Love, Penelope."
The card also featured a bunch of hearts alongside the word "family."
Barker was also celebrated by his own children, including son Landon, 18, and daughter Alabama, 16, whom he shares with ex-wife Shanna Moakler -- as well as 23-year-old stepdaughter Atiana, Moakler's daughter from her relationship with Oscar de la Hoya.
In celebration of the special day, Barker, Kardashian and their kids all celebrated with a catered outdoor dinner feast, followed by a movie projected onto a big inflatable screen in their backyard.
Kardashian took to her Instagram to share a slideshow of pics and videos from the celebration. She captioned the post simply, "Dinner and a movie."
Meanwhile, Disick shared some love with his kids for Father's Day, including a snapshot of Penelope, giving him some hilarious, embarrassed-child side-eye.
"Father’s Day every day with this little girl! ❤️," Disick wrote.
For more on Barker and Kardashian's family, and their post-wedding bliss, check out the video below.