Bangkok, Thailand – August 19, 2026 – PRESSADVANTAGE –

Siam Legal International, a full-service law firm with more than 22 years of experience assisting foreign and local nationals in Thailand, is highlighting the legal risks facing unmarried couples following a Ministerial Regulation that took effect on March 24, 2026 and standardized the procedures for registering wills at district offices nationwide. The regulation does not change the underlying inheritance rules under the Civil and Commercial Code, but it appears to tighten capacity verification, standardize registration forms, and formalize procedures for disinheritance and renunciation at the district office level.

The firm points to the update as a reminder that a valid Thai will remains the primary safeguard for unmarried partners, since Thai law does not recognize common law marriage regardless of how long a couple has lived together. The reminder comes as a growing share of adults in Thailand remain unmarried, with roughly one in five people in the country never having married, a figure that rises to more than half the population in Bangkok. The trend underscores how common long-term unmarried partnerships have become, including among foreign nationals living in the country.

Without a registered marriage, a partner whose name does not appear on a property title has no automatic legal claim to that property, no matter how much they contributed toward it. If a partner dies without a valid Thai will, an unmarried partner is not recognized as a legal heir and the estate may instead pass to statutory heirs under Thai inheritance law. Couples with children face additional complications, since a foreign biological father does not automatically receive legal parental status unless the marriage is registered or a separate legitimation process is completed.

The immigration consequences can be equally significant for foreign nationals living in Thailand. Living with a Thai partner does not by itself create any immigration benefit, and only a legally registered marriage can serve as the basis for a marriage-based visa application. This gap between emotional commitment and legal status is where many foreign nationals are caught off guard, particularly those who have built a home, finances, and family life in Thailand without formalizing their relationship under Thai law.

Rex Baay, Senior Immigration Consultant and Operations Manager at Siam Legal International, said the firm regularly advises long-term couples who assume that time together carries the same legal weight as marriage. “Many foreign nationals living with a Thai partner for years are surprised to learn that cohabitation alone provides no claim to property, no inheritance rights, and no immigration standing,” Baay said. “Putting a legal framework in place while the relationship is stable is far simpler than trying to resolve these questions after a dispute or a death has already occurred.”

Several legal options exist for couples who choose not to register a marriage. A cohabitation agreement is a private contract that allows two people living together to document how shared finances, property, and responsibilities will be managed, and while it does not create the legal status of marriage, it can provide clarity and reduce disputes. A properly drafted Thai will, now processed under updated district office procedures, remains the clearest way to ensure a partner inherits assets. For couples with children, a legitimation process allows a biological father to be formally recognized as the child’s legal parent, and couples who eventually register their marriage can use a prenuptial agreement to define ownership of assets beforehand, though it must be signed and registered at the same time as the marriage rather than afterward.

The firm recently published Siam Legal’s Thailand cohabitation rights guide, which walks through what unmarried couples in Thailand stand to lose without legal protection and outlines the steps available to reduce that risk. Couples do not need to marry to put important legal protections in place, and planning is not about anticipating failure but about protecting a home, finances, and family if circumstances change unexpectedly.

Siam Legal International is a full-service law firm with more than 22 years of experience assisting foreign nationals in Thailand, with offices in Bangkok, Chiang Mai, Phuket, and Pattaya. The firm provides comprehensive legal and immigration support across family law, property matters, business law, litigation, and residency planning.

###

For more information about Siam Legal International, contact the company here:

Siam Legal International
Rex Baay
+662 254 8900
info@siam-legal.com
18th Floor, Unit 1806 Two Pacific Place,
142 Sukhumvit Rd, Khlong Toei,
Bangkok 10110, Thailand

Media gallery

About The Author
PressAdvantage