Arbitrator independence and impartiality form the cornerstone of a legitimate arbitral process. Under section 19 of the Thai Arbitration Act B.E. 2545 (2002), prospective arbitrators must disclose circumstances likely to give rise to justifiable doubts as to their impartiality or independence, and existing arbitrators must do so throughout proceedings. This mirrors article 12 of the UNCITRAL Model Law. Yet despite this clear mandate, practical implementation varies significantly across Thailand’s arbitration landscape. Background Thailand’s two principal arbitration institutions, the Thai Arbitration Institute (TAI) and the Thailand Arbitration Center (THAC), both maintain procedures for addressing arbitrator challenges and require compliance with the statutory disclosure obligation. Under both sets of rules, any party wishing to challenge an arbitrator must submit a challenge application within fifteen days of becoming aware of the relevant facts, and a committee is appointed to consider the matter on a case-by-case basis. The TAI additionally prescribes its Code of Ethics and Conduct for Arbitrators to further emphasize the expectation of impartiality and transparency. However, Thailand’s arbitration ecosystem extends well beyond the TAI and THAC. Several sector-specific institutions also administer arbitral proceedings, including the Thai Commercial Arbitration Office under the Board of Trade of Thailand, the Arbitration Centre of the Office of the Insurance Commission, the Arbitration Centre of the Securities and Exchange Commission, the Office for the Prevention and Resolution of Disputes regarding Intellectual Property, and the Arbitration Centre of the Thai General Insurance Association. These institutions each operate under their own procedural rules, which were developed to serve particular industries and dispute profiles. The procedural mechanisms for securing and documenting an independence declaration are not uniformly established across these forums. Consequences of Procedural Inconsistency This creates a notable gap. Not all arbitration bodies have a formalized procedure requiring written independence statements before proceedings commence. Some tribunals proceed

Arbitrations seated in Thailand are governed principally by the Arbitration Act B.E. 2545 (2002) and, where applicable, the rules of institutions such as the Thailand Arbitration Center (THAC) and the Thai Arbitration Institute (TAI). While these instruments set the core procedural structure, they are not comprehensive. To fill in these procedural gaps, arbitral tribunals often look to the Thai Civil Procedure Code (CPC) and apply its principles when the Arbitration Act or institutional rules are silent. This hybrid system is familiar to local practitioners but can surprise international parties who expect a more self-contained arbitral procedure. Examples of How CPC Principles Are Applied Evidence Management: Section 25 of the Arbitration Act requires equal treatment of the parties and guarantees each side a full opportunity to present its case. At the same time, it grants tribunals broad discretion to conduct proceedings “as it deems appropriate” and expressly suggests that arbitrators may apply the CPC evidence rules where appropriate. In practice, tribunals frequently apply CPC evidence rules when addressing: submission of evidence lists, late or additional evidence, questions of admissibility and relevance, and assessment of witness and expert testimony. Amendments to Pleadings: Because the Arbitration Act and institutional rules provide limited guidance on amending pleadings, tribunals often rely on CPC principles when parties seek to amend a statement of claim or defense. Amendments may be permitted if they are sought in a timely manner, do not unfairly prejudice the opposing party, do not cause undue delay, and do not alter the nature of the dispute. These conditions closely mirror the standards applied by Thai courts under the CPC. Subpoenas and Court Assistance: Arbitral tribunals seated in Thailand generally do not have inherent subpoena powers. Section 33 of the Arbitration Act fills this gap by permitting the tribunal, an individual arbitrator, or a

Tilleke & Gibbins has contributed the Cambodia, Thailand, and Vietnam chapters to Taking and Enforcing Collateral Security and Guarantees in Southeast Asia, a comparative guide developed by Drew Network Asia (DNA). The publication examines the legal frameworks governing collateral security and guarantees across seven Southeast Asian jurisdictions and is intended to assist financial institutions, corporate borrowers, and cross-border investors in evaluating secured lending options in the region. The guide provides a practical overview of key issues relevant to taking and enforcing security interests—covering, among other topics, the types of assets that may be secured, the formalities and registration requirements for creating security, and the rights and procedures available in enforcement scenarios. Each chapter follows a consistent question-and-answer format to allow readers to compare approaches across jurisdictions easily. While the guide offers a high-level survey of the region’s collateral and guarantee regimes, it also notes that country-specific developments and transaction-specific considerations may affect the applicable requirements. Readers seeking detailed advice are encouraged to consult the lawyers listed at the end of each jurisdictional chapter. The full guide is available for download using the button below or directly from the DNA website.