Gunilla Lindberg, chair of the IOC's Coordination Commission, said inspections of venues during the three-day visit showed construction work was on target and the venues would be ready for test events over the next six months.
"Pyeongchang 2018 is entering the last stages of preparations," she said in a news release. "My colleagues and I leave here more confident than ever that Pyeongchang 2018 will deliver great Games.
"We saw first hand the progress of the construction projects. There is no doubt that the venues will be ready for the upcoming test events."
Asia's first Winter Games outside Japan will see the coastal city of Gangneung host figure skating, curling, ice hockey, speed and short-track skating events, while the alpine town of Pyeongchang will stage mountain events.
Speaking at a news conference on Friday, Lindberg hinted at delays in the signing off of legacy plans for the venues, saying it was now time to finalise the details, according to Yonhap news.
Lee Hee-beom, president of the Pyeongchang organising committee (POCOG), acknowledged the emphasis the IOC placed on venue legacy.
"This is something we'll continue to discuss even after the Olympic Games are over," he said. "We've determined after-use plans for 10 of our 12 venues. We'll finalise plans for the two remaining facilities soon."
However, with the Games set to open in less than 500 days' time, Lindberg said the biggest task was making sure the world's attention was focused on Pyeongchang when the event opened.
"The biggest challenge at the moment is how to promote the Games over the world, because this is a small place," she said, adding that Pyeongchang did not have the international standing of other Olympic host cities.
"It's not Rio de Janeiro and it's not London. We have to take action as soon as possible."
(Reporting by Peter Rutherford; Editing by John O'Brien)
