It was confirmed on Saturday that Prince Harry was to make the journey, although his wife, Meghan, the Duchess of Sussex, who is heavily pregnant, was advised against flying.
It is understood the Duke of Sussex will follow all coronavirus guidelines and regulations during his visit, but as the funeral will take place on Saturday he will be unable to complete a full period of quarantine.
However, the rules do state that a person undergoing quarantine can temporarily leave on compassionate grounds, including for funerals.
Guidance published on the Government's website states: "You can leave your place of self-isolation in limited circumstances, including on compassionate grounds.
"This includes attending a funeral of a household member, a close family member or a friend (if neither household member or close family member can attend the funeral).
"You must continue to self-isolate at all other times."
A spokesman for Buckingham Palace said the royals would be following the guidance throughout the funeral.
Mourners are also advised to be respectful of those who are clinically vulnerable from COVID-19 and "avoid close contact at any point" – potentially limiting his time with his 94-year-old grandmother.
Only 30 people – expected to be the Duke of Edinburgh's children, grandchildren and other close family – will attend.
All public elements of the funeral – to take place entirely within the grounds of the castle – have been cancelled, but it will be televised.
The couple's decision meant Prince Harry was asked to return his military appointments to the Queen.
This included the roles of Captain General Royal Marines, Honorary Air Commandant, RAF Honington, and Commodore-in-Chief, Small Ships and Diving, Royal Naval Command.
Cover image: PA.