Thailand were drawn on Tuesday into a tough group with defending champions Japan and North Korea in the AFC U23 Championship.
First-time qualifiers Palestine are the other team in Group B of the tournament, which will be held in China from Jan 9-27.
The top two teams of each of the four groups advance to the quarter-finals.
Thailand reached the 2018 finals after finishing second behind Malaysia in their qualifying group in Bangkok in July.
The Thais won the SEA Games title in Malaysia the following month.
Thailand U23 coach Zoran Jakovic said that he was pleased with the draw: "We have time to prepare the team. Judging by our potential, I believe that we can take on every team in our group. Our first goal is to qualify for the next round [knockout stage]."
Meanwhile, Malaysia and North Korea will play their delayed Asian Cup qualifiers in Thailand next month, after the matches were postponed over a diplomatic row and nuclear tensions.
The Asian Football Confederation said it chose Thailand as the neutral venue for the games on Nov 10 and 13 at a stadium which is yet to be confirmed.
The first leg was originally scheduled for March 28 in Pyongyang, but it was postponed twice after the murder of the North Korean leader's half-brother in Malaysia in February sent tensions soaring. The game was finally due to go ahead earlier this month in Pyongyang but was delayed again after Kuala Lumpur banned travel to North Korea as global alarm grew over the regime's weapons programme.