Across most Commonwealth realms – those countries in which he is monarch – the debate over whether to move to a republic is a live issue, albeit to varying degrees.
Here, BBC correspondents describe the mood in a selection of nations where King Charles is still head of state – and explore the chances of those countries replacing the monarchy any time soon.
St Kitts and Nevis
By Celestina Olulode
Spectators eyes are glued to the pitch at this cricket match. It’s a clash between local rivals, as the women’s teams from the islands of St Kitts and Nevis face off against each other. The UK’s influence remains strong here, right down to the choice of national sport.
St Kitts and Nevis is a dual-island nation situated between the Atlantic Ocean and Caribbean Sea. This was where English colonists first settled in the Caribbean. But even after almost 40 years of independence, there’s an ongoing debate about this nation’s identity, and whether it should transition to a republic.
In the spectator stands, low-level chatter is interrupted with cheers and words of advice shouted over to players. During a lull in the game I head over to ask people for their opinions.
Few are willing to express their views, but those that do are ambivalent.
Sharlene Martin says she wants more information but questions the benefit of having King Charles III as head of state: “The Chinese and Taiwanese look after us more than England, so I don’t know.”
Ahead of sunset, I head over to a local bar to chat with more locals. Manager Julian Morton says it’s a matter of national pride: “Going republic says we have arrived. So it lets the rest of the world know that we can handle our own affairs.”
Julian’s friend Christopher Roberts agrees but tells me that St Kitts and Nevis is still trying to bounce back from the negative impact of coronavirus. So he doesn’t see becoming a republic as a pressing priority: “We’re just having discussions, street talk about it.”
Compared to other Caribbean nations such as Barbados, Christopher sees St Kitts and Nevis as a “young independent nation”, and so he thinks change could take a while.
Barbados, once nicknamed “little England” took the step in 2021, renewing momentum for other realms to follow.
But for the transition to happen here, the constitution of St Kitts and Nevis requires that the people vote for it in a referendum. In fact, of the remaining eight realms around the Caribbean, only Belize would not need a referendum. Instead, the decision would be made by its national assembly.
The hurdles that referendums need to clear differ across countries. In St Lucia, the Bahamas, Jamaica and St Kitts and Nevis, referendums need a simple majority of voters to pass. But the transition could be more difficult to achieve in Antigua and Barbuda, Grenada and St Vincent and the Grenadines, because two-thirds majorities are required.
But it’s not always a done deal. In 2009, St Vincent and the Grenadines held a referendum. Forty-five per cent of voters chose to replace Queen Elizabeth II with a ceremonial president – falling far short of the two-thirds required.
So, though a seemingly simple question, these are detailed matters that each Caribbean realm is grappling with in its own way.
Australia
By Tiffanie Turnbull
Walking the streets of Sydney, you would struggle to find any sign a new King of Australia is about to be crowned.
A week out, all bar one person I spoke to admitted they did not know when the Coronation was. One student even confessed he did not know what it was.
“I don’t care, it’s irrelevant,” was 73-year-old Graham’s frank assessment – a fairly accurate picture of the general mood here.
Landmarks across the country will be lit up purple on Saturday night, but events to mark the occasion appear to be subdued and scarce.
And special television coverage of the event is limited – a far cry from the wall-to-wall treatment that royal weddings and the Queen’s funeral received.
King Charles isn’t as popular as Queen Elizabeth II was and his Coronation comes at a time when Australia’s republican movement has its strongest foothold in decades.
Almost 25 years since the country voted against cutting ties with the monarchy in a referendum, there’s growing momentum for another go.
Prime Minister Anthony Albanese has previously said a republic is “inevitable” and last year appointed a junior minister for the republic – a historic first. In nearby New Zealand it is a similar story – Prime Minister Chris Hipkins this week said he’s a republican and believes the country will “ideally” leave the monarchy one day.
The monarchy has a purely ceremonial role here in Australia and people tell me the country has long forged its own identity outside of the UK’s shadow.
Others cite the lasting impact of colonisation on Aboriginal and Torres Strait Islander people as a reason to cut ties.
“We’re probably more anti-colonial than we have ever been,” 17-year-old Estelle Paterson says.
“Having an English king here just seems so odd,” her friend Monika Januleviciute adds.
But any Republic of Australia is still years away, at least.
The government is first holding a referendum on recognising Indigenous people in the constitution.
And Australians are still divided on how to appoint a head of state – should they be elected by the people, or appointed by parliament?
But most importantly, recent polls indicate support for a republic is still below the high standard required to pass a referendum here. A majority of Australians would need to vote yes and there would also need to be majority support in at least four of Australia’s six states.
Canada
By Jessica Murphy in Toronto
If there was one word to sum up the feelings many Canadians have about King Charles, it would be “indifferent”.
And speaking broadly, while Canadians held an affection for Queen Elizabeth II, that same fondness is not felt for King Charles.
Opinion surveys suggest Canadians are growing more interested in distancing the country from the monarchy.
The most recent, an Angus Reid poll released in late April, indicates that a majority of Canadians – just over half – don’t want the country to continue as a constitutional monarchy for generations to come.
And two-in-five respondents said they didn’t care about the coming Coronation.
That lack of enthusiasm is reflected in Canada’s modest planned celebrations. There will be a televised hour-long event, hosted in the nation’s capital of Ottawa and federal landmarks illuminated in emerald green to mark the occasion.
The King’s ascent to the throne last year only served to spur debate on the country’s ties to the monarchy.
That was especially true in Quebec, where the institution is viewed more negatively than in other regions – a sentiment tied to the province’s history of being a French-speaking region once under British colonial rule.
Last December, Quebec passed a law making an oath of allegiance to the monarch optional for members of the legislature.
But none of that means that Canada will join the ranks of Barbados, Jamaica or Australia, who have had – or are having – a formal debate on the monarchy’s future.
Changing the current system would need approval from both the House of Commons and the Senate in parliament, as well as the unanimous consent of all 10 provinces – seen by most political analysts as an impossible hurdle.