President Yoon Suk-yeol left for London on Sunday to attend the state funeral of Queen Elizabeth II, kicking off a three-nation trip that will include his first address to the UN General Assembly, and summits with US President Joe Biden and Japanese Prime Minister Fumio Kishida.

Yoon's second overseas trip since taking office will also take him to Canada on the last leg.

He is set to arrive in London on Sunday afternoon (local time) and visit a Korean War memorial to honor the 56,000 British troops that fought alongside South Korea during the 1950-53 conflict, according to his office.

He is expected to then visit Westminster Hall, where the Queen lies in state, before attending a reception hosted by King Charles III to express his condolences over the monarch's death.

Yoon, who is being accompanied by first lady Kim Keon-hee, will be among hundreds of foreign dignitaries attending the Queen's state funeral at Westminster Abbey on Monday.

The president previously expressed his condolences during a visit to the British Embassy in Seoul and via Twitter, writing the Queen "had a strong belief in the cause of human freedom and left great legacies of dignity."

Following the funeral, he will depart for New York, where he will spend the biggest portion of his seven-day trip, and engage in a series of high-profile diplomatic events.

One of the highlights will be a keynote address during the General Debate of the 77th UN General Assembly on Tuesday. Yoon will make his debut on the UN stage with a speech outlining his vision for increasing solidarity among freedom-loving nations, according to his office.

The speech will also likely underscore South Korea's commitment to defending peace against the threat of nuclear weapons and other weapons of mass destruction, together with its allies, such as the United States.

Other highlights will be Yoon's first-ever summit with Kishida on the sidelines of the UN gathering and a separate summit with Biden. The meetings will likely take place either Tuesday or Wednesday, according to his office.

The Yoon-Kishida meeting will be the first summit between the two countries since December 2019 and raises hope of improving relations badly frayed over wartime forced labor and other issues related to Japan's 1910-45 colonial rule of the Korean Peninsula.

The two leaders held a trilateral meeting with Biden on the margins of the North Atlantic Treaty Organization (NATO) summit in Madrid in June, and had several other encounters during events there, but did not sit down for one-on-one talks.

The meeting with Biden will be Yoon's second since taking office in May following their summit in Seoul that month.

The two are expected to discuss the implementation of agreements reached during the May summit but also address South Korea's concerns about the recently passed US Inflation Reduction Act.

The law excludes electric vehicles assembled outside North America from tax incentives, raising concerns it will act as a significant trade barrier for Korean-made cars.

Yoon's itinerary in New York also includes separate meetings with UN Secretary-General Antonio Guterres and Korean residents Tuesday, as well as various sessions with academics, scientists, and businesspeople, and a reception hosted by Biden at the American Museum of Natural History on Wednesday.

On the third and final leg of his trip, the president will fly to Canada on Thursday, a country that sent 27,000 troops to fight alongside South Korea in the Korean War, and shares the values of human rights and a liberal democracy, according to his office.

Yoon will stop first in Toronto to meet with world-famed artificial intelligence scholars and exchange opinions on expanding cooperation between South Korea and Canada. The president will then meet with Korean residents in the city.

From Toronto, Yoon will head to Ottawa on Friday for a summit with Canadian Prime Minister Justin Trudeau and discuss ways to deepen the bilateral strategic partnership ahead of the 60th anniversary of establishing diplomatic ties next year.

Canada is a key producer of core minerals used in the production of EV batteries, with South Korean businesses planning large-scale investments in Canada's battery sector, according to the presidential office.

Yoon will return home Sept. 24. (Yonhap)