Thailand's same-sex marriage legislation, scheduled to come into effect in January 2025, could attract an additional 4 million tourists to the country per year, according to a report commissioned by the travel company Agoda.

The report published Thursday estimates the country's marriage equality law may increase tourism arrivals by 10%, netting the country an extra $2 billion in tourism revenue per year, within two years.

Arrivals are expected to come, not only from same-sex couples and their wedding guests, but from the broader LGBTQ community and beyond.

"Thailand is set to attract a growing number of travellers and expatriate workers who seek not just a vacation spot but a place where they can feel truly accepted," according to the report, titled "The Economic Impact of Marriage Equality on Thailand's Tourism Industry."

Thailand's new legislation — scheduled to go into effect on Jan. 22, 2025 — is projected to add 76,000 full-time jobs to its tourism industry, while raising the country's gross domestic product by .3%, according to the report from the public policy consultancy Access Partnership.

The new law will make Thailand the third place in Asia to allow same-same marriage, following Taiwan in 2019 and, on a more limited basis, Nepal in 2023. The law is also set to grant same-sex couples rights related to child adoption, health care and inheritance.

Calculating the impact

To calculate the potential economic impact of Thailand's new legislation, the report examined the effect of same-sex marriage legislation in other countries.

"Other markets, such as New Zealand and the United States, saw notable increases in same-sex weddings following introduction of marriage equality legislation," Timothy Hughes, Agoda's vice president of corporate development, told CNBC Travel.

New Zealand legalized same-sex marriage in 2013. By 2016, the majority of same-sex weddings in the country were for visitors, the report said.

Australians made up more than half (58%) of same-sex weddings in New Zealand from 2013 to 2017, according to the report citing Statistics New Zealand. This figure fell to 26% in 2017, after Australia passed its own same-sex marriage law, it said.

Agoda's report also analyzed other factors that influence international tourists, including the attractiveness of a destination, the affordability of travel, the ease of entrance, and the perceived level of acceptance of LGBTQIA+ issues.

Finally, the report also considered the availability of viable alternative destinations for LGBTQIA+ or travelers in the region.

"Within 5 hours flying of Thailand are more than 3.6 billion people in markets that do not have marriage equality," said Hughes.

He highlighted the economic opportunity from Indian travelers, predicting Thailand will become a top destination "for Indian LGBTQIA+ couples and those ready to celebrate with them."

A 'unique strategic opportunity'

The planning, for some, has already begun.

Ann Chumaporn, a Thai rights activist and co-founder of Bangkok Pride, said her organization is arranging a mass wedding event for same-sex couples on Jan. 23, 2025 — the first day that marriage registrations can be filed, she said.

"We have over 300 couples registered, and our goal is to reach 1,000 couples nationwide," she told CNBC Travel. "We already have international couples registered."

The Thai government also has its sights set on hosting WorldPride, a global pride event that netted New South Wales $185.6 million Australian dollars ($120 million) when Sydney hosted in 2023, according to Agoda's report.

Rainbow tourism, as it is known, is valued at $200 billion worldwide, according to the report.

In an era of fierce competition for tourists — especially whose who splurge on weddings and related celebrations — Thailand has a "unique strategic opportunity," said Marcus Ng, director of Access Partnership.

"While we cannot predict what other markets might do, what this report demonstrates is that there is a clear economic benefit to inclusivity for both the tourism sector and the wider economy."