In my last article, I compared matrimonial property regimes in Switzerland and Thailand and drew some parallels. Now, based on a more critical analysis, I will look more closely at prenuptial agreements in binational marriages. For Swiss-Thai couples in particular, there are significant pitfalls if the couple later emigrates to Thailand (e.g., retirements) and relies on a Swiss prenuptial agreement.

A purely Swiss prenuptial agreement is rarely recognized in Thailand, dual agreements are complicated and not always practical, and Thai prenuptial arrangements are limited in scope. A one-to-one mirror solution is not possible.

The limitations of Thai prenuptial agreements compared with Switzerland

Under Swiss law (Swiss Civil Code, Art. 181 et seq.), prenuptial agreements can regulate matrimonial property regimes in a comprehensive way, from participation in acquired property to separation of property, including detailed provisions on inheritances, debts, or alimony payments. In Thailand (Civil and Commercial Code, Sections 1465–1469), prenuptial agreements are possible, but they are much more restricted:

• Limited scope: Thai agreements can only regulate the classification of assets (Sin Suan Tua = personal property vs. Sin Som Ros = marital property), but they cannot include provisions that violate Thai law, for example, foreign ownership restrictions regarding land (foreigners may not own land). Complex Swiss-style clauses on pension assets, international wealth, or alimony are mostly not enforceable, as they may be considered “unfair” or contrary to public policy.
• Formal hurdles: The agreement must be made in writing before the marriage (in Thai or bilingual form), notarized, and registered with the Amphoe (district office) at the time of marriage registration. Without this, the default property regime applies.

Therefore, a Thai prenup is not “equally comprehensive” compared with a Swiss one. It mainly helps to protect against debt risks or unwanted mixing of assets, but not against all international complications.

The problem with dual prenuptial agreements

Some experts recommend a “dual” approach: one agreement under Swiss law (notarized in Switzerland) and a separate one under Thai law (registered in Thailand). In practice, however, this is often hardly workable or comes with considerable risks:

• Compatibility issues: The two agreements must be harmonized in substance, which is difficult. For example, a Swiss separation of property clause could be considered invalid in Thailand. Courts in both countries may also arrive at contradictory results.
• Additional costs and complexity: Separate lawyers in both countries, translations, and registrations make the process expensive. And if the marriage is concluded in Switzerland, direct registration of the Thai prenup in Thailand is often not possible, because the Thai agreement generally has to be registered at the time of the Thai marriage registration.
• Risk of non-recognition: A Swiss agreement may at best be partially respected in Thailand if it meets Thai standards, which will rarely be the case. Conversely, a Thai prenup may be recognized in Switzerland under private international law, but only if it is considered fair. In most cases, however, couples want to regulate more than a Thai prenup legally allows.

In short: dual agreements are theoretically possible, but in practice often impractical and full of potential for conflicts.

Registration issues where the marriage is concluded in Switzerland

This is a particularly critical point: if you marry in Switzerland, the marriage must be separately registered in Thailand, for example through the Thai embassy or at an Amphoe, in order to have legal effects there. But a Thai prenup cannot simply be registered afterward; it must be concluded before or at the time of the Thai marriage registration. This means that if the marriage is concluded in Switzerland, full Thai registration of the prenup is often impossible, because simultaneous or pre-registration at the Amphoe is usually difficult to achieve. The result is a gap: the Swiss agreement applies in Switzerland, but not in Thailand. Thailand will generally not recognize the prenuptial agreement in Thai divorce proceedings, and enforcement of a Swiss judgment in Thailand can also be very difficult.

Conclusion and recommendations

Prenuptial agreements in Swiss-Thai marriages are not a simple protection mechanism, they require a careful and critical assessment of the risks. Dual agreements are rarely seamless, Thai prenuptial agreements are limited in scope, and where the marriage is concluded in Switzerland, Thai registration is often missing.