Prince George, Princess Charlotte and Prince Louis all made their first public appearances on the steps of the Lindo wing.
The Duke and Duchess of Cambridge introduced their three children to a bank of photographers and cameras outside St Mary's Hospital in Paddington, London.
Future king Prince George weighed 8lb 6oz when he was born in 2013, and the duke and the duchess said in a statement that they "could not be happier".
George was first seen on the steps of the Lindo Wing, wrapped in a white shawl.
Doll-like Princess Charlotte made her debut outside the Lindo in 2015.
A cream bonnet was tied under her chin and she was also wrapped in a merino wool blanket.
The youngest Cambridge sibling, Prince Louis, arrived on patriotic St George's Day in 2018, and was also pictured sleeping outside St Mary's Hospital just hours after he was born.
William joked he had "thrice the worry" as he took the prince home to Kensington Palace.
Princes William and Harry also made their debuts at the Lindo, in the arms of their mother Diana, Princess of Wales and alongside their father the Prince of Wales.
Princess Anne also unveiled her eldest son – the Queen's first grandchild – outside the hospital.
Peter Phillips was born at the Lindo and headed home on Anne's lap as she was driven from the hospital in 1977.
When Lady Louise Windsor, who was born prematurely, was finally allowed home in 2003, a beaming Earl and Countess of Wessex were pictured with their daughter at Frimley Park Hospital in Surrey.
With a long tradition of royal babies being born at home, many were not seen until official pictures had been released.
Prince Charles, now the Prince of Wales, was born at Buckingham Palace – the Queen had all four of her children at home.
The first glimpse of baby Charles came a month later on his christening day in December 1948.
His birth was the first in centuries without a government minister present to witness the arrival of a future heir to the throne.