“Happy birthday @kourtneykardash everyone who knows you loves you so much!” Disick, 32, captioned the photo, which was taken in 2009.
In the pic, Disick and Kardashian, 37, share an embrace and a kiss in the middle of the water.
In March, the mother of three joined Snapchat, documenting a full day of hanging out with the father of her kids – Mason, 6, Penelope, 3, and Reign, 1. Fielding speculation that their lengthy hangout meant a rekindling was in the works, Kardashian posted another video and clarified their relationship.
“By the way everyone relax, people that have three kids together spend time together,” the Keeping Up With the Kardashians star said in the clip.
Despite the sweet throwback photo Disick shared, he’s not the one Kardashian is spending her birthday with.
In videos shared on sister Kim Kardashian West’s‘s Snapchat, the birthday girl celebrated in Iceland – despite some difficulties with their helicopter ride – with Kim, brother-in-law Kanye West, and family friend Jonathan Cheban.