The spouse who didn't sign: Section 1476 consent and buying land from a married Thai seller

Can a Thai seller's spouse undo your purchase after the fact, just because they never agreed to it? Yes, in principle — Civil and Commercial Code Section 1476 requires both spouses' written consent before one of them alone can sell, exchange, mortgage, or lease for more than three years any sin somros (marital property, property acquired during the marriage). If that consent is missing, Section 1480 lets the other spouse sue to revoke the sale. It doesn't make the transaction automatically void, and a genuinely good-faith buyer has a defence — but it's a document gap worth closing before you sign, not after a dispute lands.

What Section 1476 actually requires

• Joint consent is required for specific transactions only — selling, exchanging, mortgaging, leasing for more than three years, or granting a usufruct/servitude/superficies over land or a house classed as sin somros. Everyday management of marital property doesn't need it.
• Consent must be in writing (Section 1479) for a land or house transaction — a verbal nod from the other spouse isn't enough to satisfy the law, even if both spouses later agree the sale was fine.
• Sin somros vs sin suan tua matters first. The requirement only bites if the land is marital property in the first place. Property the Thai spouse owned before marriage, or received individually as a gift or inheritance, is sin suan tua (separate property) and can be sold without the other spouse's consent — see Protecting a foreign spouse's interest during a Thai marriage for how that separate-property line gets drawn and documented in practice.

What happens if consent was never obtained

Section 1480 doesn't make an unconsented sale void outright — it's voidable. The non-signing spouse can file suit to revoke it, but only within one year from the date they learned of the sale, or ten years from the sale itself, whichever comes first. Critically, the law also protects a buyer who acted in good faith and paid genuine consideration: a court weighs whether the buyer knew, or should have known, that the seller was married and that the property was marital, before deciding whether to unwind a completed, registered transfer. That defence exists, but it depends entirely on what the buyer's due-diligence file can show — which is exactly why this is a document to collect at signing, not an argument to make in court afterward.

What to check before you pay

• Confirm marital status first. A Thai national's house registration book (tabien baan) or a marriage certificate search at the district office (Amphur) establishes whether the seller is married and, if so, since when — relevant to whether the land was acquired before or during the marriage.
• If married, get the spouse's written consent to the specific sale, ideally on the same document set the Land Office will review at transfer, not a separate side letter that could go missing from the file.
• If the seller claims the land is sin suan tua (separate property), ask for the documentary basis — a title deed dated before the marriage, or a gift/inheritance deed naming the seller individually — rather than taking the claim at face value.
• Have your lawyer confirm this alongside the rest of the standard checks in the due-diligence checklist and the land office registration day process — the Land Office clerk may ask for a spousal consent form as a matter of routine practice even though it isn't a universal statutory filing requirement for every transfer.

None of this changes who can hold Thai land as a foreigner — that's still governed by the Land Code, not the marital-property rules. What Section 1476 changes is how solid the title is that you're paying for: a sale by a married seller without their spouse's documented consent carries a real, if time-limited, risk of being unwound. A short paper trail collected before registration closes that gap.