Few legal disputes are as personally bruising as a marriage broken by infidelity. Thailand offers a clear civil remedy for the wronged spouse, and following the 2025 reform of Section 1523 of the Civil and Commercial Code that remedy is now available equally to all spouses regardless of gender or sexual orientation. This guide explains exactly how an adultery damages claim works in Thailand, what evidence is needed, how Thai courts fix the amount of compensation, and the strict one-year deadline that catches many claimants by surprise.

Adultery Is a Civil Wrong, Not a Crime, in Thailand

Thailand does not criminalise adultery. No spouse, paramour, or third party can be jailed simply for an extramarital affair. The remedy lies entirely in the civil sphere, governed by Book V of the Civil and Commercial Code (CCC) on Family. The aggrieved spouse may sue for monetary damages, and adultery is one of the recognised grounds for filing a petition for divorce.

The two civil consequences run on parallel tracks. A spouse may pursue a damages claim against the unfaithful partner and the third party without filing for divorce. Equally, a spouse may file a divorce petition based on adultery and pursue compensation in the same proceedings. The choice depends on the outcome the aggrieved spouse wants: a financial award, the dissolution of the marriage, or both.

The Statutory Framework: Sections 1516, 1523, 1524 and 1525 CCC

Four provisions of the Civil and Commercial Code together create the legal architecture for an adultery claim in Thailand. Reading them in sequence makes the system intelligible for clients who often arrive expecting criminal penalties.

Two paragraphs of Section 1523 work differently in practice. Paragraph 1 attaches the right to compensation to a divorce decree pronounced on adultery grounds. Paragraph 2 stands alone: a spouse may sue the third party for damages without seeking divorce at all. The latter route is often selected when the aggrieved spouse wishes to preserve the marriage but seeks a financial remedy and a deterrent against the third party.

The 2025 Reform: A Gender-Neutral Adultery Law

Until early 2025, Section 1523 paragraph 2 drew a sharp line between husbands and wives. A husband could sue any person who took adulterous liberties with his wife. A wife, by contrast, could sue only another woman, and only one who had openly displayed an affair with her husband. Same-sex relationships sat outside the framework altogether because same-sex marriage was not yet recognised.

The Constitutional Court swept that imbalance away in Judgment No. 13/2567 dated 18 June 2024, holding that the previous wording of Section 1523 paragraph 2 violated Section 27 of the Constitution by treating men and women unequally. Parliament responded with the Civil and Commercial Code Amendment Act (No. 24) B.E. 2567 (2024), which entered into force on 23 January 2025 together with the Marriage Equality Act. The amendment replaced the gendered language of "husband and wife" with the neutral term "spouse", with three practical consequences:

• A wife may now sue a man, a woman, or any other adult who had an adulterous relationship with her husband, on identical terms to a husband suing his wife's paramour.
• Same-sex spouses, lawfully married since 23 January 2025, have full standing to bring an adultery damages claim under Section 1523 on equal terms.
• The cause of action no longer depends on whether the affair was conducted "openly" by a man, while women must still show open conduct only against a same-sex paramour outside marriage; the rule is now uniform for all spouses.

The reform is procedural in spirit. The substance of the cause of action survived. Only the gendered restrictions disappeared. Courts continue to apply the same evidentiary standards and damage assessment principles described below.

Who Can Be Sued for Adultery in Thailand

Two categories of defendant are exposed to a claim under the post-2025 Section 1523. Each carries different practical considerations.

The Unfaithful Spouse

The aggrieved spouse may sue his or her partner for compensation only as part of a divorce judgment under Section 1516(1). Outside divorce, intra-spousal damages are not awarded for adultery itself. A spouse who wishes to recover from the partner must therefore couple the claim with a divorce petition.

The Third Party (Paramour, Mia Noi, or Equivalent)

The third party may be sued whether the aggrieved spouse files for divorce or not. The plaintiff must show one of two things:

• That the third party engaged in sexual relations with the spouse, or
• That the third party openly presented himself or herself as having a sexual relationship with the spouse, for example through public displays of affection, social media announcements, cohabitation, or holding the relationship out to family, neighbours, or colleagues.

A third party who genuinely did not know the spouse was married is still legally liable. Thai courts treat lack of knowledge as a mitigating factor when fixing the compensation amount, not as a complete defence. Conversely, a paramour who knew of the marriage faces enhanced exposure.

Evidence Required to Prove Adultery

A successful claim depends on quality evidence. Thai courts apply the civil standard of proof, namely preponderance of the evidence, but the plaintiff carries the burden, and family judges are accustomed to seeing clear, contemporaneous documentation. The following categories of evidence are typically persuasive in Thai practice:

• Photographs and video showing the spouse and third party in compromising circumstances, in shared accommodation, or attending events together as a couple
• Hotel and travel records, including booking confirmations under joint names, room-share invoices, immigration stamps showing simultaneous travel, or property rental agreements
• Digital communications, such as messages, emails, voice notes, and image exchanges that disclose intimacy
• Social media evidence, including public posts, tagged photographs, profile pictures, and relationship status declarations
• Witness testimony from neighbours, household staff, friends, or relatives who observed the relationship
• Birth certificates and DNA evidence where a child has been born from the affair
• Financial records showing gifts, transfers, jointly held accommodation, or payments toward the third party's living expenses

Evidence collected unlawfully, for example through hacking the spouse's private account or covert recordings inside private premises that violate the Computer Crime Act B.E. 2550, can be excluded and may even expose the plaintiff to criminal liability. Most experienced family lawyers in Thailand recommend retaining a licensed private investigator who understands the boundary between admissible surveillance and illegal intrusion.

How Thai Courts Calculate Compensation

Section 1525 gives the Court explicit discretion to fix the compensation amount according to the circumstances of each case. There is no statutory ceiling and no statutory floor. In practice, awards in Thailand for adultery damages typically range from 100,000 to 1,000,000 THB, with higher figures in cases involving public exposure, lengthy affairs, or high net-worth defendants. Courts weigh a combination of subjective and objective factors:

Where both the unfaithful spouse and the third party are sued, the Court may apportion the total award between them. Under Section 1525 the Court may also direct payment in instalments, particularly where the defendant lacks immediate liquidity.

The One-Year Deadline: Section 1529 CCC

Section 1529 imposes a strict statute of limitations: an action for adultery damages must be filed within one year from the date the aggrieved spouse knew, or ought to have known, of the facts giving rise to the claim. The clock does not start on the day the affair began. It starts on the day of discovery, or on the day reasonable diligence would have revealed the affair.

A continuing affair effectively keeps the claim alive. Thai courts have repeatedly held that while the relationship between the spouse and the third party is ongoing, each day of continuation refreshes the cause of action and the one-year period has not yet conclusively started. Once the relationship ends, the year is counted from that date or from the date of discovery, whichever is later.

Foreign spouses living outside Thailand sometimes lose claims because they delay filing while seeking advice in their home country. The deadline runs irrespective of nationality, residence, or location of the parties, and applies regardless of whether the marriage was registered in Thailand or recognised from abroad.

Step-by-Step Procedure for an Adultery Damages Claim

A typical adultery damages action in Thailand follows a recognisable sequence. Timelines vary with court workload, defendant cooperation, and whether divorce is pursued in parallel.

Stage 1: Evidence Gathering and Pre-Action Assessment

Counsel reviews the marriage documentation, the relationship history, and any evidence already in hand. A licensed investigator may be engaged to fill evidentiary gaps lawfully. Counsel calculates an indicative compensation figure and confirms the limitation period under Section 1529 has not lapsed.

Stage 2: Drafting and Filing the Plaint

The plaintiff's lawyer drafts the plaint specifying the parties, the cause of action under Section 1523, the requested compensation amount, and the supporting evidence. The plaint is filed at the Court of First Instance for the district where the defendants reside or where the cause of action arose. Family matters in Bangkok are usually filed at the Central Juvenile and Family Court, while regional cases proceed before the local provincial court's family division.

Stage 3: Court Fees Payable on Filing

Court fees follow the schedule under the Civil Procedure Code. For monetary claims:

A plaintiff seeking 500,000 THB in damages therefore pays approximately 10,000 THB in court fees on filing. The fee is recoverable from the losing party at the end of the proceedings.

Stage 4: Service, Answer, Mediation

The Court summons the defendants. Each defendant must file a written answer within fifteen days of service, extendable on application. Family courts in Thailand routinely refer cases to court-annexed mediation before any contested hearing. Many adultery damages claims settle at this stage, often with confidentiality undertakings that protect the parties' reputations.

Stage 5: Trial and Judgment

If mediation fails, the Court schedules a witness hearing. Each side presents documentary evidence and calls witnesses. The Court then renders judgment, fixes the compensation amount under Section 1525, and orders single or instalment payment.

Stage 6: Appeal and Enforcement

Either party may appeal to the Court of Appeal for Specialised Cases within one month of the judgment. Once the judgment is final, the plaintiff may enforce it through the Legal Execution Department, including by attaching bank accounts, garnishing wages, or seizing the judgment debtor's property.

Defences and When You Cannot Claim

Section 1523 expressly bars compensation in two situations:

• Consent or connivance. A spouse who consented to the relationship or knowingly tolerated it cannot sue. Open marriages, accepted "Mia Noi" arrangements, and any documented permission undermine the claim.
• Spouse-permitted conduct. Where the aggrieved spouse permitted the third party's conduct, the claim against that third party is barred.

Other defences regularly raised at trial include:

• Time-bar under Section 1529 (more than one year since discovery and the affair has ended)
• Insufficient evidence that the relationship was sexual or openly displayed
• Genuine ignorance of the marriage by the third party (mitigates damages even if it does not bar the claim)
• The marriage was already dissolved when the alleged conduct occurred, or the parties were already de facto separated
• The plaintiff's own concurrent adulterous conduct, which the Court may consider when fixing the amount

Practical Notes for Foreign Claimants

Foreign nationals married to a Thai spouse, or foreigners married to each other under Thai law, have full standing to bring an adultery damages claim. Several practical points often matter:

• Marriage registration. Only a marriage registered in Thailand or recognised by Thai law triggers protection under Section 1523. Religious ceremonies, common-law cohabitation, and engagement events without registration do not create a right to adultery damages.
• Translation and legalisation. Foreign documents, including foreign marriage certificates, must be translated into Thai and legalised through the Thai Ministry of Foreign Affairs and the relevant embassy.
• Power of attorney. A plaintiff abroad may authorise a Thai lawyer to act through a power of attorney legalised at the Thai embassy or consulate.
• Currency of award. Compensation is awarded in Thai baht. Foreign claimants should consider exchange exposure when valuing the claim.
• Tax treatment. A damages award for adultery is generally not subject to Thai personal income tax, but foreign tax residents should obtain advice in their home jurisdiction before receipt.

How Juslaws & Consult Can Help

Family disputes are emotionally charged, and adultery cases sit at the intersection of evidence-gathering, court strategy, and reputation management. Our family law team handles adultery damages claims, divorce petitions, custody, and the international dimensions that arise when one spouse is foreign or assets are held overseas. We work on confidential terms, coordinate licensed investigators where appropriate, and file in both Bangkok and the provinces. If you are weighing a claim under Section 1523, contact us for a confidential consultation before the one-year limitation period under Section 1529 narrows your options.

Frequently Asked Questions