Britain's King Charles III smiles during his visit to the Forsinard Flows Visitor Centre in Forsinard, Highland, Scotland, July 31, 2024. Pool Photo via AP

LONDON — King Charles III has announced plans to visit Australia and Samoa next month on a trip that will span a dozen time zones and test the monarch’s stamina as he recovers from cancer treatment.

The Oct. 18-26 tour, which Buckingham Palace outlined Tuesday, marks a watershed moment for the 75-year-old king.

Charles is slowly returning to public duties after taking a break following his cancer diagnosis in early February. The decision to undertake such a long journey will be seen as a sign of his recovery.

The trip will begin in Australia before the king and Queen Camilla travel to Samoa for the Commonwealth heads of government meeting, which takes place every two years. Although the tour was first announced in July, no dates were released at that time.

Charles’ globetrotting itinerary comes as he works to shore up support for the monarchy at home and abroad two years after becoming king. The stop in Australia will mark the first time since Charles ascended the throne that he will visit one of the so-called Commonwealth realms, the 14 countries outside the United Kingdom where the monarch remains head of state.

Australian Prime Minister Anthony Albanese has a long-held aim of holding a referendum on breaking ties with the monarchy and declaring his country a republic. But those plans were put on hold after Australians overwhelmingly rejected a plan to give greater political rights to Indigenous people in a referendum held last year.

Charles will travel to Samoa as the head of the Commonwealth, a voluntary association of 56 independent nations, most of which have historic ties to the U.K.

“The king’s visit to Australia will be his majesty’s first to a realm as monarch, whilst the Commonwealth Heads of Government Meeting in Samoa is the first the King will attend as head of the Commonwealth,” the palace said in a statement. “In both countries, their Majesties’ engagements will focus on themes designed to celebrate the best of Australia and Samoa, as well as reflecting aspects of the king and queen’s work.”