His latest update was another peek into the sweet time spent with his youngsters as he accompanied them to swimming lessons.
To mark the adorable milestone with the young trio, Irwin shared a snap of Rafa, Rex and Cormac sat by the side of a pool looking out to the water.
"Swimming lessons," Irwin captioned the adorable post. "Proper dad vibes watching my trio today."
Jonnie Irwin regularly shares updates with his three kids
Of course, it didn't take long for fans to share their thoughts on the heartwarming family moment.
One fan replied: "It’s always the small things that are the normal things that are the best things xx."
While a second added: "You are one hell of a real dad! An amazing one at that. They now have another memory.
"My birth dad never once came to my swim or dance lessons - not one! You keep doing what you can for as long as you can. You have us all behind you xx."
Elsewhere, another praised: "Top top Dad Jonnie. One day in the future those boys will look back and be so proud of you. Keep going and all power to you."
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And a fourth echoed: "So you should, your a wonderful Dad with gorgeous boys! A heart of a lion!"
"Aww such a beautiful photo Jonnie," commented a fifth. "You should have dad vibes. You deserve dad vibes. You are dad vibes. You bloody trooper. You are like an army tank. No stopping you. Keep on going general Irwin."
Jonnie Irwin sparked concern earlier this week when he revealed his cancer had spread
But revealing it has spread further, Irwin shared a snap of himself in an oxygen mask at a treatment centre as he penned: "The wait for more scans is frustrating when you know the cancer is on the move again.
"Meanwhile there’s stuff I can do to make the terrain as tough as possible for growth and the ladies down at @sereniti_health are part of my team of suppliers for various therapies.
"I’d recommend this place to anyone wanting to tap into a healthier lifestyle. Big shout as always goes to @how_to_starve_cancer who’s constant help has a huge impact. #respect."