Following their fun-filled day, the 17-year-old wildlife conservationist took to Instagram to share a snap of her holding hands with Powell and her mother, Terri Irwin.
"This photo makes me so happy," she wrote. "Taken by my gorgeous little brother [Robert], of my beautiful Mum and amazing boyfriend. Family honestly means everything. How blessed am I? Here's to a lifetime more of holding hands and skipping down hallways with those that you love."
Last December, Irwin also took to social media to thank Powell, 19, for "always making me smile."
"Pretty much sums up our relationship…," she captioned an adorable video of the two on a hike.