It was the first time the Duke and Duchess of Cambridge and their three children have been seen together as a family of five.
We can't wait to see more photos!
Leaving the church with her family after the christening, the three-year-old looked up at the waiting paparazzi and told them that they weren't invited to the reception at Clarence House.
After the brief speech, the Queen joined the rest of the royals up on the palace balcony to watch nearly 100 aircraft, from Second World War Spitfires to the newest stealth fighter jet, fly over the palace.
And just yesterday, the Duchess of Sussex attended Prince Louis' christening wearing a deep green bespoke Ralph Lauren draped dress-paired with a low, slick ponytail.More news: Why China Is Losing the Trade War
More closely, Kate is a former RAF wife herself, with William having earned his wings - along with Prince Charles, Prince Philip and King George VI - in 2008.
The Queen led the celebrations and she watched the flypast from the balcony of the palace.
Nicholas Van Cutsem, Harry Aubrey-Fletcher, and Guy Pelly are Prince Louis' godfathers.
Kate is now in the middle of maternity leave for Prince Louis and hasn't yet returned to full-time royal duties.
Meghan, the new Duchess of Sussex, wore a dress by Dior and hat by royal milliner Stephen Jones.
Elsewhere, Sophie Carter - who already acts as a godmother for three-year-old Princess Charlotte - is among the list, and so is Lucy Middleton, a cousin of the Duchess.