The King has arrived at the Commando Training Centre Royal Marines at Lympstone in Devon, where he trained as a helicopter pilot.
The 76-year-old monarch, who holds the title of the Captain General of the Royal Marines, will present the King’s Badge and a Green Beret to two specially selected trainees on Friday.
This will be the first time a king has presented the badge since his grandfather King George VI in 1939.
It has been made even more significant as this year marks the 360th birthday year of the Royal Marines.
The visit comes just a day after the King celebrated his 76th birthday on Thursday.
He spent the day working as he opened the first two Coronation Food hubs, including one in person.
The hubs – which are major distribution centre designed to save and circulate tonnes of surplus food – are set to transform the ability of charities like FareShare and the Felix Project to support communities in need.
After opening the first Coronation Food Hub at the Deptford Trading Estate in south London yesterday, school children from Rye Oak Primary School in Peckham presented the King with a large birthday card that featured a collage of photographs in the shape of 76, made by six-year-old pupil Zariah.
The childen then sang Happy Birthday to the King who was pictured beaming and in good spirits.
Later in the day, the King then opened the second food hub in Liverpool virtually.
He could be heard saying: “Please give my kindest wishes to everybody there, and I hope it makes an enormous difference to all their remarkable work that they do with so many different communities who need it so valuably. I hope you have a great success with those huge freezers.”
Queen Camilla was set to attend the events with the King but is still recovering from her chest infection.