They joined their father, King Charles III, and other members of their family for the historic moment.
Queen Elizabeth II's body has left Buckingham Palace for the last time. Mourners came out in droves on Wednesday to see the historic procession of the late British monarch as her coffin traveled from Buckingham Palace to Westminster Hall.
Other royals included in the procession were Elizabeth's other children, Princess Anne, Prince Andrew, and Prince Edward. Both Harry and Andrew were not wearing their military uniforms as both have stepped down as senior members of the royal family in recent years.
On Tuesday, a spokesperson for the Duke of Sussex released a statement to royal reporters about Harry's reaction to not being allowed to wear his uniform despite his decade of service.
"Prince Harry, The Duke of Sussex, will wear a mourning suit throughout events honoring his grandmother," the statement read. "His decade of military service is not determined by the uniform he wears, and we respectfully ask that focus remain on the life and legacy of Her Majesty Queen Elizabeth II."
The royal family, including Harry and his wife, Meghan Markle, received the queen's coffin at Buckingham Palace on Tuesday evening.
William and Harry, who have been estranged in recent years, made a similar walk back in April 2021 when they appeared in the procession for their grandfather, Prince Philip's, funeral.
Historically, they also walked in the procession for their mother, Princess Diana's, 1997 funeral, which both brothers have discussed at length.
"It wasn't an easy decision, and it was a collective family decision to do that," William said of the tragic march in the BBC Documentary Diana, 7 Days. "It was one of the hardest things I've ever done."