President Park Geun-hye was greeted Tuesday by the queen and Prince Philip as she arrived at Horse Guards Parade in London.
The queen then introduced Park to dignitaries including Prime Minister David Cameron and Foreign Secretary William Hague.
Park traveled by a carriage procession to Buckingham Palace, where she will be staying during her three-day visit.
The last South Korean leader to make a state visit to the U.K. was Roh Moo-hyun in 2004.
Elizabeth and Philip paid a state visit to Seoul in 1999.