Kate Middletonand her three kids —Prince George,Princess CharlotteandPrince Louis— know no day outdoors is complete without a picnic!

WhilePrince Williamand Prince Harry faced off in acharity polo matchon Wednesday, George and Charlotte were busykicking around a soccer balland showing off dance moves. But after so many activities, it was time to retreat to the car for a snack break.

Kate took a seat on the grass withPrince Louis, 1, while Prince George, who wore a green polo and camo shorts, and Princess Charlotte, who wore theMarie-Chantal “Celina” dress, hung out in the back of the car with the trunk popped open.

An onlooker tells PEOPLE, “George seemed to be saying, ‘Charlotte pass me the sandwiches.’ Kate was asking Charlotte to pass little pots of food, and she also helped herself to food.”

These pictures “showed real life,” the onlooker adds.

Kate Middleton, Prince Louis, Prince George and Princess Charlotte.Tim Rooke/Shutterstock

Catherine Duchess of Cambridge, Prince Louis, Prince George, Princess Charlotte

Catherine, Duchess of Cambridge, Prince Louis of Cambridge, Princess Charlotte of Cambridge and Prince George of Cambridge attend the King Power Royal Charity Polo Match, in which Prince William, Duke of Cambridge and Prince Harry, Duke of Sussex were competing for the Khun Vichai Srivaddhanaprabha Memorial Polo Trophy at Billingbear Polo Club on July 10, 2019 in Wokingham, England

Another observer says, “Louis had a Tupperware pots and was chewing on a freezer pack from a cool bag. She took a Tupperware tub out and he was munching on carrot or pepper sticks.”

Catherine, Duchess of Cambridge, Prince Louis of Cambridge, Princess Charlotte of Cambridge and Prince George of Cambridge attend the King Power Royal Charity Polo Match, in which Prince William, Duke of Cambridge and Prince Harry, Duke of Sussex were competing for the Khun Vichai Srivaddhanaprabha Memorial Polo Trophy at Billingbear Polo Club on July 10, 2019 in Wokingham, England

But while George, 5, was goofing off — climbing over the back seat of the car to get into the trunk — Charlotte, 4, was trying to enjoy her meal (from a lunchbox with a heart on top!).

“She sat there eating out of her lunchbox as she sat on the boot of the car,” the observer says. “She was looking at George as if thinking, ‘What on earth are you doing? I’m sitting here having a nice picnic, and you’re rolling around like a lunatic!’ ”

Catherine, Duchess of Cambridge, Prince Louis of Cambridge, Princess Charlotte of Cambridge and Prince George of Cambridge attend the King Power Royal Charity Polo Match, in which Prince William, Duke of Cambridge and Prince Harry, Duke of Sussex were competing for the Khun Vichai Srivaddhanaprabha Memorial Polo Trophy at Billingbear Polo Club on July 10, 2019 in Wokingham, England

Catherine, Duchess of Cambridge, Prince Louis of Cambridge, Princess Charlotte of Cambridge and Prince George of Cambridge attend the King Power Royal Charity Polo Match, in which Prince William, Duke of Cambridge and Prince Harry, Duke of Sussex were competing for the Khun Vichai Srivaddhanaprabha Memorial Polo Trophy at Billingbear Polo Club on July 10, 2019 in Wokingham, England

The royal kids are no strangers to the polo field. Last summer, George and Charlotte joined their cousins — Savannah and Isla Phillips, the daughters of the Queen’s grandson Peter Phillips — for amemorable playdate at another one of their dad’s charity polo matches.

“The first thing they did when they left the car was slide down the hill on his bum,” an onlooker told PEOPLE at the time. “George was peering over some hoarding around the side of the pitch, grinning at the others, who were messing around with him.”

“Kate is a fantastic mom,” the observer added. “She was calm with the children.” Using a British phrase for “run loose,” the onlooker said, “She let them have their head.”

Prince George and Princess Charlotte.SplashNews.com

Princess Charlotte and Prince George

Princess Charlotte.James Whatling/MEGA

Princess Charlotte and Prince George

Meghan Marklewas also at the family day out with her 2-month-old sonArchie— marking the royal cousins’ first public playdate together.

Tim Rooke/Shutterstock

Mandatory Credit: Photo by Tim Rooke/Shutterstock (10331673az) Meghan Duchess of Sussex, Archie Mountbatten-Windsor, Catherine Duchess of Cambridge King Power Royal Charity Polo Day, Billingbear Polo Club, Wokingham, UK - 10 Jul 2019

It was a warm, sunny day, and Meghan mainly stayed under the shade of a tree with her son in her arms.

“She was doting on him, there’s no doubt about that,” the onlooker tells PEOPLE. “She was kissing and stroking him and bouncing him up and down.”

source: people.com