The Cambridge family attended the Platinum Pageant on The Mall, marking the final event of the Jubilee weekend.
Senior royals joined extended family members to watch the parade combining street arts, theatre, music, circus, carnival and costume to celebrate Her Majesty’s 70 year reign.
Following the pageant, the Cambridges, along with Prince Charles and The Duchess of Cornwall joined the Queen on the Buckingham Palace balcony to close the celebrations.
Princess Charlotte and her eldest brother, Prince George accompanied their parents on a trip to Wales today as part of the Queen's Platinum Jubilee.
The Cambridges visited Cardiff Castle to meet performers and crew involved in the special Platinum Jubilee Celebration Concert taking place in the castle grounds later this afternoon.
Kensington Palace uploaded a video on Sunday showing the Cambridge children helping their mum prepare some baked treats for the Platinum Jubilee street parties which will take place all across the UK today.
The cupcakes were made ahead of their visit to Cardiff yesterday.
Princess Charlotte joined her eldest brother, Prince George and their parents for the Queen's Platinum Jubilee Party at the Palace on Saturday evening.
The Duke and Duchess of Cambridge shared this clip following the party.
Today marks the first day of the Platinum Jubilee weekend and the 70th anniversary of Queen Elizabeth II's Coronation. The celebration kicked off with the Queen's Birthday Parade, the Trooping the Colour.
Princess Charlotte joined her family for the celebrations and started the day off in a traditional horse carriage procession down The Mall. She was accompanied by her mother, The Duchess of Cambridge, her two brothers, Prince George & Prince Louis, and her step grandmother, The Duchess of Cornwall.
Following the parade, the Cambridge family joined Her Majesty on the balcony at Buckingham Palace for the traditional RAF fly-past.
Princess Charlotte wore a cornflower blue Patachou chiffon dress (£77) with flutter sleeves and decorative bow at the neck. ID by @foundbybojana.
She had a section of her hair up in braids and secured with a blue ribbon.