The Caribbean country is one of 14 nations to retain the British monarch as their head of state, with prime minister Gaston Browne signing a document confirming Charles’ status as the new King.
But minutes later, he said he would push for a republic referendum after indicating such a move earlier this year during a visit by the Earl and Countess of Wessex.
Mr Browne told ITV: “This is not an act of hostility or any difference between Antigua and Barbuda and the monarchy, but it is the final step to complete that circle of independence, to ensure that we are truly a sovereign nation.
“I’d say probably within the next three years,” he added, when asked for a timeframe on the referendum.
Mr Browne in April called on the Wessexes to use their “diplomatic influence” to achieve “reparatory justice”, and outlined his country’s wish to “one day become a republic”.
The earl was criticised as “arrogant” for joking that he had not been taking notes during Mr Browne’s comments.
William and Kate, meanwhile, were accused of harking back to colonial days in Jamaica in March after the pair shook hands with crowds behind a wire mesh fence and rode in the back of a Land Rover, just as the Queen had done 60 years prior.
Demonstrators accused them of benefiting from the “blood, tears and sweat” of slaves, while in the Bahamas they were urged to acknowledge the British economy was “built on the backs” of past Bahamians and to pay reparations.
Jamaica’s prime minister Andrew Holness suggested to William and Kate that his country may be the next to become a republic, while a minister from Belize said afterwards that perhaps it was time to “take the next step in truly owning our independence”.
William acknowledged after the trip that the monarchy’s days in the Caribbean may be numbered as he stated the future “is for the people to decide upon”.
Mr Browne told ITV on Saturday his country would remain a committed member of the Commonwealth, even if it removes the monarchy via referendum.
And Antiguans were hopeful about the future despite the potential for significant change, with resident Anna Crick saying of the late Queen: “It’s all about the love that we have for her and the passion we have. Although we are independent – we honour our own – we still look up to her.”