While the sources say "nothing is final," a visit by Moon to North Korea would be the first time a South Korean President has stepped foot in the country since 2007.
A potential date could be August 15, the day Korea was liberated from Japanese occupation in 1945, a holiday marked by both Koreas.
The invitation for Moon to go north could be made at a scheduled welcome luncheon on Saturday, several diplomatic sources with deep knowledge of North Korea's intentions told CNN.
South Korea's presidential spokesman confirmed Friday that Moon plans to meet Kim Yo Jong and three other high-level delegates on the sidelines of the Winter Olympics Saturday.
The spokesman said there would be no comment on the possibility of a visit by the South Korean leader to Pyongyang.
A private jet carrying the North Korean delegation touched down at South Korea's Incheon International Airport on the outskirts of Seoul around 2 p.m. local time, ahead of the Opening Ceremony.
The US has made it clear it's not pleased about North Korea's overtures to the South.
Leading the US delegation in Pyeongchang, Vice President Mike Pence said he's there to ensure the Games aren't hijacked by North Korean propaganda.
Despite the scheduled high-level meeting, Pence said there was "no daylight" between the United States and South Korea on their North Korea policy.
"We don't want to repeat the mistakes of the past. President Moon and I reflected on that last night. And that denuclearization has to be the starting point of any change, not the end point of any change," Pence told reporters Friday.
Kim Yo Jong is the first member of North Korea's ruling family to go to South Korea since the 1950-1953 Korean War.
Sources say an informal luncheon between Kim and the South Korean delegation would give her more freedom to interact with the South Koreans than anybody else in the North Korean delegation.
Hosting an informal lunch for the high level North Korean delegation avoids any protocol format where only one main speaker has a voice. That main speaker would normally be Kim Yong Nam, the head of the delegation and North Korea's ceremonial head of state.
Both sides are maintaining a delicate balance to avoid any diplomatic upsets that could risk overshadowing the Winter Olympics.
On the eve of the Games, North Korea staged a parade involving thousands of soldiers marching in unison, planes soaring above and four of Pyongyang's newest and most sophisticated missiles, the Hwasong-15.
North Korean leader Kim Jong Un watched all of it from a balcony above and gave a rousing speech in which he warned about the dangers of imperialism in the world.
Sources say it was noteworthy that North Korean leader Kim Jong Un didn't mention the word "nuclear" during his speech, instead choosing to refer to his country as having "developed into a world class military power."
Images broadcast on North Korean state television showed huge formations of people marching in unison, and row of tanks and weapons. However sources say the parade plans were "scaled down at the last minute."
South Korean President Moon is seeking to continue a meaningful dialogue with North Korea, but he's also under pressure from the United States to disengage from Pyongyang after the Olympics and join Washington in a campaign of "maximum pressure."
Sources said an invitation for Moon to visit North Korea may be a continuation of Pyongyang's efforts to drive a wedge between Seoul and Washington.
While North Korea has stated it has no intention of meeting with the United States at the Olympics, Kim Yo Jong is expected to use her visit to South Korea to attempt to thaw relations with China, which has been stepping up enforcement of unprecedented sanctions against North Korea, resulting in billions of dollars in trade losses for both countries.