Johnson singled out the 1988 Olympic Village as an "amazing" example of how to sell apartments in advance to help raise money for the site.
The British government has had to dip into a contingency fund to help build the Olympic Village because of a lack of private financing during the economic recession.
Johnson praised the sculpture garden, parks, glades and waterside features at the 1988 Olympics site in southeastern Seoul. Johnson says he also watched hundreds going for a swim in the Olympic Games pool Monday.