A man and two women handed over to ICRC officials, ending Afghan kidnap drama.
Taliban and Afghan officials have also denied that a ransom was involved.
But Alan Fisher, reporting for Al Jazeera from Kabul in Afghanistan, quoted sources as saying that the “Taliban left the table substantially richer” and that the ransom could have been as high as $20m.
The hostages were relased in separate groups on Wednesday and Thursday and reunited at the hotel in Kabul.
Two of the former hostages recounted their ordeal before they left for Dubai on Friday.
The bus had picked up two locals along the way and one of them had pointed his gun at the driver and told him to stop, 55-year-old Yu Kyeong-Sik said in comments reported by South Korea’s Yonhap news agency.
“When the driver ignored him, he opened fire and the bus stopped. The Taliban told him to move the bus to the side and fired a bullet into a tyre. Then two armed men came up and beat the driver and told all of us to get off.”
Yu said he and another man were driven away on a motorbike for about 10 minutes along an unpaved road to a village. The others were brought along later.
The 23-strong party was then split into five groups. Yu said his own group changed places 12 times, moving from village to village at night by motorbike or on foot.
Two female hostages had been released earlier in what the Taliban called a “gesture of goodwill” during talks with the South Korean delegation.
Two colleagues who were captured with them on July 19 had already been shot dead.
The remaining hostages were freed after Seoul restated its decision to withdraw its small military presence in Afghanistan – about 200 people comprised mainly of medical workers and engineers – by the end of the year.
Angela Merkel, the German chancellor, said Berlin would stand firm in its refusal to negotiate over a German engineer captured by the Taliban more than six weeks ago.