The Commonwealth Day events are the most significant annual royal occasion that Charles, 75, will miss since he was forced to postpone public appearances while he undergoes treatment for an unspecified form of cancer.
His wife Queen Camilla will instead lead senior royals when they gather for a service at London's Westminster Abbey followed by a reception at Commonwealth's international headquarters.
In a pre-recorded video message to be played during the service, Charles will pay tribute to the work of the voluntary club of 56 nations which evolved out of the British empire and was set up in its current form in 1949.
"As I have said before, the Commonwealth is like the wiring of a house, and its people, our energy and our ideas are the current that runs through those wires," he says in his message.
Charles will not be the only senior royal who will be absent on Monday. Kate, wife of his eldest son and heir Prince William, will not attend as she continues her recovery from abdominal surgery.
On Sunday, she released her first public message alongside a photograph of her and their three children, taken by William last week, in which she looked happy and healthy.
For most of its existence, the Commonwealth, one of the world's biggest international organisations covering 2.5 billion people, was led by Charles' late mother Queen Elizabeth who was instrumental in its creation and regarded it as one of her proudest achievements.
"Having recently celebrated my own seventy-fifth birthday, it warms my heart to reflect on the way the Commonwealth has been a constant throughout my own life – a precious source of strength, inspiration, and pride," Charles says in his message.
"In recent weeks, I have been most deeply touched by your wonderfully kind and thoughtful good wishes for my health and, in return, can only continue to serve you, to the best of my ability, throughout the Commonwealth."
