Thailand's King has endorsed a marriage equality bill passed by parliament earlier this year, officially making the kingdom the first country in Southeast Asia and third place in Asia to recognise marriages of same-sex couples.

The royal endorsement was published in the official royal gazette late on Tuesday, meaning the bill will come into force in 120 days, which would be Jan 22, 2025.

The law, the culmination of two decades of efforts by activists, was approved by the Senate in June.

Thailand, one of Asia's most popular tourist destinations, is already known for its LGBT culture and tolerance.