Last year, the administration of Mr. Moon offered to donate $8 million to two United Nations humanitarian programs working in North Korea. Mr. Moon suspended the plan after international pushback that the offer might undermine United Nations sanctions against the North’s nuclear weapons and missile programs.

In Pyeongchang, South Korea will pay for the joint uniforms to be worn by athletes of both sides during the opening ceremony, and foot the bill for housing and feeding hundreds of North Korean dancers and cultural entertainers who will perform during the Games. However, no money will go directly to them, South Korean officials have said.

The North Koreans are also quite likely to be the only athletes not to receive a free smartphone from the Olympic sponsor Samsung. South Korean officials said they were eager to dispel concerns, particularly in Washington, that they were making payments to the North that could violate sanctions.

“We are trying to brief the Americans so thoroughly about every detail of matters concerning sanctions and the North Korean delegation that they get tired of hearing it,” said Cho Myoung-gyon, who as South Korea’s unification minister is in charge of dealings with the North.

The I.O.C. first urged North and South Korean sports officials to meet in 1963, a time when East and West Germany had created a joint Olympic squad. But the two Koreas could get no further than deciding that a hypothetical joint squad would use a well-known Korean folk song, “Arirang,” instead of picking one of their national anthems.

They agreed to talk again before the Los Angeles Olympics in 1984. But when they met on their shared border, the heavily fortified Demilitarized Zone, the talks quickly devolved into mutual recriminations. South Korea demanded that the North apologize for its bombing of Mr. Chun’s presidential delegation in Burma the previous year, which killed 17 South Koreans, while North Korea called Mr. Chun a “bloody-handed” dictator for ordering the massacre of protesters in the city of Kwangju in 1980.