A total of 12 teams played in the tournament, with players born on or after 1 January 2004 eligible to participate.

Indonesia Thailand Malaysia Myanmar Vietnam Laos Timor-Leste Cambodia Singapore Brunei Philippines Australia The top two teams of each group advance to the semi-finals.

[4][5] The protest was subsequently admitted upon compliance of the procedural requirements set out in the 2019 Tournament Regulations with the AFF began to carrying out the necessary investigation and have requested the parties involved to collaborate to establish the facts.

In accordance to the tournament regulations, the conclusion of the investigation will be decided by the AFF Disciplinary and Ethics Committee.

[7] On 4 August, the AFF announced their findings that the said player is deemed to be eligible to participate in the tournament in accordance with Article 5.1 as stated in the tournament regulations and ruled the protest lodged by two countries as unfounded and dismissed it accordingly.