The U.K. defense ministry said that batteries will fire 41 rounds at one round every minute from midday in cities including London, Edinburgh, Cardiff and Belfast, as well as Gibraltar and from Royal Navy warships.
Prince Philip died Friday at age 99. Buckingham Palace is expected to announce details of the funeral later on Saturday.
It is likely to be a small, private affair, stripped of the grandeur of traditional royal occasions by COVID-19 restrictions and by the prince’s own dislike of people making a fuss.
Despite a request from the royal family for the public to obey pandemic social distancing rules and avoid visits to its residences, people laid cards and bouquets outside Windsor Castle and Buckingham Palace through the night.
“What a life! Thank you for serving our country,” read one tribute outside Buckingham Palace.
Flags at Buckingham Palace and at government buildings across Britain were lowered to half-mast and billboard operators replaced adverts with a photo and tribute to the prince.
The BBC cancelled programming across all of its television and radio channels on Friday, and aired a special programme with interviews with the queen and Philip’s children, including heir-to-the-throne Prince Charles.
Gun salutes also marked the deaths of Queen Victoria in 1901 and Winston Churchill in 1965.
Authorities are encouraging to watch the gun salutes online or on television from home amid the coronavirus pandemic.
The Associated Press and Reuters contributed to this report.