The 35-year-old actor and 46-year-old singer spent the holiday with their 5-year-old twin children, daughter Monroe and son Moroccan, at the Sky Zone Trampoline Park.
The family outing came just days after Cannon released the song "Divorce Papers."
The freestyle rap addresses the actor's divorce from Carey and his concerns over their custody arrangement.
"Leaving the haters in the wind! LOL They want us to be mad so bad! @MariahCarey but we happier than happy! #HappyFathersDay," he captioned a photo of himself with Carey, their kids and his mom at the park.
Cannon had told Karen Civil he recorded the song to vent about the frenzy surrounding his split from Carey.
He denied the rap was intended "to feed the tabloid chatter" and insisted he and the singer are on good terms.
"This was strictly a creative way for me to express my frustrations with the media, the naysayers, myself and ultimately the voices in my head," the actor explained.
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"My ex and I are in a great place and are diligently moving things along so we both can continue to be happy," he added.
"I am happy for her and all her new endeavors, both personal ones and professional ones."
Cannon and Carey split in 2014 after six years of marriage.
The singer has since gotten engaged to businessman James Packer, although she and Cannon often spend time together with their children.
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