The brother-sister duo stole hearts as they attended a children's party for military families at their Government House base in Victoria.
Prince George and Prince William arrived hand-in-hand, while Princess Charlotte was carried in on Duchess Catherine's hip.
Listen to Charlotte call Wills "dada" in the video above!
16-month-old Charlotte looked divine in a pastel blue sundress with a pink sash by Pepa & Co., which retails for £74.
Her trademark blue bow and matching shoes finished off the ensemble.
At the party, Charlotte was particularly entranced by the balloons. At one point the little princess pointed at the colourful display and remarked "pop!"
The beautiful Princess had the crowd in stitches when she met Moose the dog and decided to sit on him!
WATCH: The hilarious moment Charlotte meets Moose. Post continues after the video...
Moose, who is a Labrador-Poodle cross and is a companion dog for cancer patients, clearly wasn't fussed by Charlotte's antics.
We wonder if Lupo is used to getting that kind of treatment back home?
Meanwhile big brother George, who looked smart in a navy jumper and beetroot-coloured shorts, loved playing with the bubble machine but proved nothing beats mum's hugs when he looked around and asked for his "mummy."
George also took a liking to the miniature horses and rabbits in the petting zoo.
At the garden party, there was also a balloon artist on hand and a petting zoo to entertain the royal children and guests.
Prince William and Duchess Catherine once again displayed how attentive and loving they are as parents, showering their two children in cuddles and kisses.
Princess Charlotte, who was born on May 2nd, 2015, has also reached another massive milestone - she's walking!
The one-year-old confidently strutted around the garden party like a pro.
And the fourth-in-line to the British throne seems to be quite the chatterbox, too.
During a conversation with William, he asked her, "Do you want a balloon Charlotte?"
To which she replied, "Yeah!" Later she could be heard trying to summon her father by calling him "Dada." Aww!
WATCH: The royal sibling play with each other! Post continues after the video...
The family dynamics of The Cambridges were heartwarming to observe.
Prince George proved siblings will always have a slight rivalry when he spotted sister Charlotte at the balloon stand.
The young Prince immediately stopped patting a rabbit and raced over to his mum and Charlotte and asked, "But I want one! Can I have one?"
The Duchess continued her high-fashion streak in a stylish cream dress by designer See By Chloe.
This marks the second engagement the siblings have made on the Royal tour following their arrival in Victoria last Saturday.
"The Duke and Duchess are really pleased to have this opportunity to introduce their children to Canada and it's great that they have the chance to play with other children while they are here," a spokesperson for the family said.
Earlier in the week, The Duke expressed his excitement at being able to introduce his children to Canada.
"Catherine and I are delighted to be back in Canada. When we were here last time, we had been married only three months. The warm welcome that you gave us at that important moment in our lives meant a lot to us – and we have never forgotten it,"
"We are so pleased that George and Charlotte can be with us... beginning their own lifetime of friendship with this wonderful country," the 34-year-old said in a keynote speech on Saturday.
It's been a jam-packed week of engagements for the Cambridges but the focus of their trip has been family-friendly and low-key.
They've visited places like Yukon, Whitehorse, Vancouver and Bella Bella.
During their trip, they've requested to meet with people from "all walks of life" as they try to shine a light on issues close to their heart like mental health, drug addiction and the re-settlement of refugees.