Chandler popped the question shortly after Bindi's 21st birthday in the gardens of their Australia Zoo home.
Bindi's younger brother Robert was even in on the surprise and secretly photographed the moment when Chandler went down on one knee.
"On my birthday I said ‘yes’ and ‘forever’ to the love of my life," Bindi wrote in an Instagram post shortly after the proposal.
"Chandler, close to six years ago I fell in love with you and every day since has been a whirlwind of adventure and true happiness. I’m so looking forwarding to spending our forever together as your wife. Here’s to a lifetime of friendship, purpose and unconditional love. — Now let’s get married already!"
The couple wed in a secret ceremony in March just hours before government restrictions were put in place due to the coronavirus.
"We thought about postponing, because you want to share this day with everyone, but when it boiled down to it, we both just said, 'Look, we desperately want to get married, and no matter what the future holds, at least we’ll be husband and wife. We can take on the world together,'" Bindi said when explaining why they rushed to get married.
Though many of their loved ones were unable to attend the ceremony, Bindi's mum Terri was present, as was brother Robert, who walked Bindi down the aisle in place of their late dad Steve.
Steve Irwin died unexpectedly in 2006 but the couple made sure he wasn't forgotten on their wedding day by lighting a candle in his honour.
"I think it's really special that he's always with us and he walks beside us with everything that we do," a tearful Bindi said at the wedding, with her new husband adding that in a way, Steve brought the two together.
"He was my hero growing up and it means the world that he's always here with us," Chandler said.