https://www.samuiforsale.com/law-texts/thai-act-on-conflict-of-law.html
Section 22 – Thai Conflict of Laws Act (B.E. 2481)
“As regards property of husband and wife, if there is no antenuptial (prenuptial) agreement, the law of nationality shall govern. If the husband and the wife are of different nationalities, the law of nationality of the husband shall govern.
However, in respect of immovable property, the law of the place where it is situated shall govern.”