International Arbitration 2026

THAILAND Law and Practice Contributed by: Phatsawat Siwawej, Piyachon Jiraratmethakorn and Ketsirin Wisetwatcharawong, Weerawong C&P

Without the instant enforceability of the award incor - porated into the court’s judgment, it lacks interna - tional enforceability under the New York Convention. Despite these provisions, in-court arbitration has sel - dom been utilised in Thailand, likely due to insufficient public awareness. 3.4 Validity Thailand recognises the rule of separability for arbitra - tion clauses. It is considered an independent agree - ment separate from the main contract. Consequently, even if the arbitral tribunal determines that the main contract is null and void, this decision does not affect the validity of the arbitration clause. As stipulated in Section 11 of the Thai Arbitration Law, an arbitration agreement can take the form of an arbitration clause within a contract or exist as a separate agreement altogether. Further reinforcing the distinctness of arbitration clauses, Section 24 of the Thai Arbitration Law confirms their separability. This provision ensures that any invalidity of the primary contract does not impact the legality of the arbitra - tion clause contained therein. In instances where a claimant presents a case contain - ing a seemingly legally enforceable arbitration clause before a Thai court, the court does not immediately dismiss the case. Instead, it provides the defendant with the opportunity to raise an objection. Subse - quently, the court is mandated to conduct an inquiry hearing to determine the enforceability of the arbitra - tion clause under the provisions of the Thai Arbitration Law. Generally, if an arbitration agreement appears to be legally binding and complies with the Thai Arbitra - tion Law, the Thai court will likely dismiss the case and thereby compel the parties to proceed with the arbitral process. A generally binding arbitration clause may, however, become unenforceable should it be contained in a standard form contract that gives the party prescrib - ing such contract an unreasonable advantage over the other party. A relevant example is a dispute between a consumer and a business operator where the busi - ness operator’s standard form contract required any dispute between the parties to be resolved by arbitra - tion. Here, the Supreme Court ruled that the agree -

ment to arbitrate was an unfair contract term due to its effect of increasing the consumer’s burden while at the same time reducing the consumer’s rights to specialised proceedings under the Consumer Case Procedure Act, BE 2551, which is part of the Thai con - sumer protection regime (Supreme Court Judgment No 4183/2565 (2022)).

4. The Arbitral Tribunal 4.1 Limits on Selection

The Thai Arbitration Law does not limit the parties’ autonomy to select arbitrators. It is furthermore the obligation of the arbitrator to disclose any circum - stances that might lead to justifiable doubts regard - ing their impartiality or independence. It is incumbent upon the arbitrator – from the moment of appointment and throughout the entirety of the arbitral proceed - ings – to promptly disclose such circumstances to all involved parties, unless the parties had previously been made aware of these by the arbitrator them- selves. 4.2 Default Procedures If the parties are unable to reach a consensus on the number of arbitrators, the arbitration process will pro - ceed with the appointment of a sole arbitrator. In situations where the tribunal should consist of a sole arbitrator and the parties fail to agree on who this arbitrator should be, either party may petition the competent court to appoint the arbitrator on the par - ties’ behalf. In cases where the arbitral tribunal consists of more than one arbitrator, each party shall appoint an equal number of co-arbitrators, and the appointed co-arbi - trators are then tasked with appointing a presiding arbitrator. If a party fails to appoint its co-arbitrator(s) within 30 days of receiving notification to do so from the other party, or if the parties’ appointed co-arbitra - tors fail to appoint the presiding arbitrator within 30 days from their appointment, either party may petition the competent court for an order appointing the co- arbitrator or the presiding arbitrator.

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