But perhaps the most heartwarming moment from her special day was when she accepted a beautiful painting from a fan of her late father, Steve Irwin.
Opening up about the Crocodile Hunter, Bindi said it's always hard to celebrate milestone without her dad around.
"What gets to me are those moments when I’d love him to be here to share what we’re doing," Bindi recently told Stellar. "It could be when my brother is receiving an accolade for his photography, or it might be at the end of the day when we’re having dinner and laughing. I’ll think: I wish Dad was here for this. But he’s just not there."
But the family had plenty of support on her big day, with Terri posting a beautiful tribute to her daughyer on social media.
"My dearest @BindiIrwin, happy 21st birthday. So many memories," the mum-of-three wrote. "Your first birthday cake, laughs with your dad, & endless family adventures."
Longtime love Chandler wrote, 'Beautiful Bee, I love you so much.
"You’re my best friend and whole world. I can’t wait to celebrate your birthday ‘at #AustraliaZoo ❤️ Here’s to another year and beyond of life-changing adventures together."