Technical article
Does My US Will Work for My Condo in Mexico City or Thailand?
So the treaty rule is not what carries a US will into Mexico or Thailand.
Picture a couple from Colorado who own a condo in Mexico City and have talked about another in Thailand. Their will was made at home. If one of them died, would the Mexican or Thai office accept it for the condo?
The treaty that does not list them
A treaty from 1961, the Hague Convention on the form of wills, says a will is valid in form if it meets any one of several connecting laws. It has 42 parties. Among them are Australia, Austria, Belgium, Denmark, France, Germany, Ireland, Japan, the Netherlands, Spain, Switzerland, the UK, South Africa and Turkey. Italy and Portugal have signed but not joined.
The list does not include the US, Mexico, Canada, Colombia, Thailand, the United Arab Emirates, Costa Rica or Panama. The source is the treaty body's status table (tier A). So the treaty rule is not what carries a US will into Mexico or Thailand. Each country's own rules decide.
Mexico
Mexican law gives a will worldwide effect. It has no forced shares for children. It does allow alimony claims against the estate by a minor or disabled descendant, a parent without means, and a spouse or partner unable to work. A person may make a will from age 16.
For assets in Mexico, Chambers (tier B) says a local will for local assets has to refer to the main will and be homologated, meaning formally recognised in Mexico. Mexico is not a party to the Hague Succession Convention, so recognition of a foreign will is case by case. Chambers recommends separate wills in each country. A trust adds a point: a Mexican fideicomiso needs a bank authorised by the banking regulator to act as trustee.
Thailand
A Thai will needs two witnesses and must be signed and dated. Thai law governs Thai land by its location. For movable property it follows the domicile of the person at death. There are no forced shares.
A foreign will may be effective, but translation and authentication may be needed. A Thai source (tier C) puts probate at 3 to 6 months with a Thai will and 12 to 24 months or more with a foreign will alone. Thai inheritance tax is 5% for a descendant above THB 100 million (about US$3 million) and 10% for others; for others the starting amount is reported as THB 10 million by one source and THB 50 million by another.
Two others on the list
| Place | What the sources say |
|---|---|
| Panama | A foreign notarised will is accepted when legal where made and apostilled; no forced shares; no estate or succession tax |
| United Arab Emirates | A non-Muslim resident may have the home-country law apply on death; a will registered in a financial-centre court can cover worldwide assets |
The Panama points come from a law firm (tier C). The United Arab Emirates points come from Withers (tier B), with land and joint assets held with a Muslim still exposed.
You could
You could list where each asset sits and which country's law governs it. You could ask a local lawyer in Mexico City whether a short local will, referring to the main one, would be recorded. You could ask the same in Thailand, and whether the US will would need a translation. You could also keep the signed originals and certified translations in one place that your executor knows about.
Who it touches
A spouse and children are the people closest to it. An executor who lives in the US meets a local office in a language not their own. A child who lives in Mexico may be the person at the notary's desk.
If you own a condo abroad, what did the notary or lawyer ask you to sign? Share it here. Someone may be about to make the same list.
Figures are estimates for planning, based on public data. Date read: October 2026.
Sources
- Hague Conference on Private International Law, status table of the 1961 wills convention (A)
- Chambers Succession and Estate Planning 2026 on Mexico (B)
- Withers on the UAE (C)
- ThaiLawOnline on Thai wills (C)
- Pardini law on Panama (C)
Tell us in the comments