Bindi and Robert Irwin Pay Tribute to 'Grandpa Crocodile' Steve Irwin 16 Years After His Death

Steve Irwin's memory is living on through his children and grandchildren, years after his death.

Bindi Irwin and brother Robert Irwin paid tribute to their late dad with some sweet childhood throwback photos Sunday for Australian Father's Day, which also happened to be the 16th anniversary of the Crocodile Hunter star's death.

Robert, 18, shared a snap of Steve holding him as a baby, writing: "It's Father's Day today in Australia, and I am sending my love to those who are missing their dad today. I cherish all the good times with my dad and feel grateful to be able to keep his memory and legacy alive."

"Grandpa Crocodile, I know you would've been the most incredible grandfather because you were such an extraordinary dad. Thank you for being an amazing guardian angel for Grace," wrote Bindi, 24, posting a photo of herself holding a baby croc while sitting in a boat with dad.

She and husband Chandler Powell welcomed their first child, daughter Grace Warrior, 17 months, last March. The couple tied the knot in 2020.

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Bindi previously explained that Grace's middle names are a tribute to her grandfather, who died at age 44 in 2006, after he was fatally stung by a stingray.

"Our graceful warrior is the most beautiful light," she wrote on Instagram. "Grace is named after my great-grandmother, and relatives in Chandler's family dating back to the 1700s.

"Her middle names, Warrior Irwin, are a tribute to my dad and his legacy as the most incredible Wildlife Warrior. Her last name is Powell, and she already has such a kind soul just like her dad," Bindi added.

The Crikey! It's the Irwins star previously opened up to PEOPLE about how they keep Steve's memory alive for their baby girl.

"We have so many documentaries of Dad, and we're always playing them for Grace," she said in May. "It's so fun to watch her study him. I didn't realize how much Dad's passion for life and his animated facial expressions — I mean, they captivate her."

RELATED VIDEO: Bindi and Robert Irwin Post Touching Tributes to Late Dad on Steve Irwin Day: 'I Still Look Up to Him'

Bindi added: "I definitely see parts of [Dad] in Grace. His determination and his inability to sit still. I think that's really special. I'm excited to see as she grows up how her personality will develop. If Dad was around, honestly, we would never see her. He would be in love."

Terri Irwin previously paid tribute to Steve for their 30th anniversary in June, writing: "I married this incredible bloke 30 years ago today. What an adventure! Love and legacy live on."