The landmark decision paves the way for Thailand to become the first Southeast Asian country to recognise equal marriage rights, and the third country in Asia after Taiwan and Nepal.

After living without access to the basic rights and security that heterosexual couples enjoy, Lesbian couple Voro Wanan and Ticha say this is a day-long overdue.

The bill passed the upper house in a landslide, after the lower house previously cleared the bill in a near-unanimous vote.

The new laws will give same-sex couples in Thailand rights on adoption, inheritance and tax allowances.

References to men, women, husbands and wives will also be changed to gender-neutral terms.

The bill had overwhelming public support, but some activists have criticised the new laws for failing to recognise transgender people and people with non-binary gender identities.

Speaking at Bangkok's Pride Parade earlier this month, the country's Prime Minister was already confident the bill would pass.

This is an opportunity for equality and equality of choice.

This month we have a big celebration.

Today is a good start.

The Prime Minister is set to open his official residence to the LGBTQ plus community and supporters to celebrate, before a parade marches from government house to Bangkok's central business district.

The legislation will now be sent to the cabinet for approval before it goes to the king for royal assent, something that's seen as a mere formality.

The new laws will come into force 120 days after publication in the official Royal Gazette.

And activists hope the first same-sex weddings can be celebrated as early as October.

And teacher and 401 say they will tie the knot as soon as possible.

When the law is passed, we will go and register.

We've been waiting for a long time.

When we get a confirmation or a positive view, it gives us strength.

As well as being a landmark in equal rights legislation, many people believe the decision will drive up the economy, with many same-sex couples set to wed.

The move could also attract more LGBTQ people to the country, and Thai activists hope it will encourage other countries in the region to follow their lead.

Alex Chen and Rosie Greninja for Taiwan Plus.