This year Father's Day was on September 4. The date also marked 16 years since Steve Irwin passed away.
Bindi Irwin and Robert Irwin shared photos on their Instagram and paid tribute to their late father.
Bindi posted a photo of her with her dad when she was younger holding a rat and sitting on a boat.
"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" Bindi wrote.
Bindi explained that her daughter Grace's middle names are a tribute to her grandfather Steve Irwin.
"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 wrote.
Robert also shared a photo of him with his dad when he was a baby.
"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 ❤️" he wrote.