How to Bring a Commercial Suit in Thailand: Procedure, Timeline & Practical Steps (2026 Update)

Last updated: 1 August 2026

Understanding the commercial litigation procedure in Thailand is essential for any business, domestic or foreign, that needs to enforce a contractual right, recover a debt, or defend against a commercial claim in the Thai courts. This guide walks claimants and defendants through every stage of the process, from pre-action assessment to enforcement of judgment, and sets out the documents, costs and statutory deadlines that apply. It also addresses two developments reshaping the procedural landscape in 2026: the Board of Investment’s latest administrative guidance for promoted companies and Thailand’s accession steps toward the Hague Apostille Convention, both of which affect how foreign evidence is authenticated and used in Thai proceedings.

Overview of the Commercial Litigation Procedure in Thailand

A “commercial suit” in Thailand encompasses any civil action arising from a business or commercial transaction, breach of contract, shareholder disputes, debt recovery, agency and distribution disagreements, insurance claims, and banking or finance litigation. The governing procedural framework is the Civil Procedure Code (พระราชบัญญัติวิธีพิจารณาความแพ่ง), supplemented by the substantive rules of the Civil and Commercial Code. Both statutes are maintained in the official repository of the Office of the Council of State (KRISDIKA).

Claims are heard by the Courts of Justice under the Office of the Judiciary. Depending on the nature and value of the dispute, proceedings may be filed in:

• Civil Courts (ศาลแพ่ง). The default forum for commercial disputes in Bangkok; provincial courts handle matters outside the capital.
• Central Intellectual Property and International Trade Court (CIPITC). Handles IP disputes and international trade matters.
• Specialised commercial and economic divisions. Certain courts operate dedicated commercial case-management tracks designed to accelerate complex business disputes.

Where the parties have agreed to arbitration, particularly common in joint-venture, construction and cross-border supply agreements, the Thai Arbitration Act applies and the courts will generally refer the matter to arbitration upon application. This guide focuses on court-based proceedings. Readers considering or currently facing a commercial claim in Thailand should treat it as a practical roadmap to be used alongside qualified legal counsel. To connect with experienced practitioners, consult the Thailand commercial lawyer directory.

Eligibility and Prerequisites for Filing a Commercial Claim

Who May Bring a Claim

Any natural person or legal entity with standing, meaning a direct, legally protected interest in the dispute, may file a commercial suit. Thai-registered companies sue through their authorised directors. Foreign companies that are not registered in Thailand may also bring claims, provided they demonstrate legal personality under their home jurisdiction and appoint Thai counsel with a properly executed power of attorney. The Civil and Commercial Code governs capacity and standing requirements.

Foreign claimants should note that Thailand does not impose a general requirement for security for costs on overseas plaintiffs, although the court retains discretion to order it in specific circumstances.

Jurisdiction and Forum Selection

Jurisdiction for commercial disputes in Thailand is determined by the defendant’s domicile, the place where the cause of action arose, or the location of the disputed property. Forum-selection clauses in the underlying contract are generally respected, subject to public-policy limits. BOI-promoted entities should check whether their promotion certificates or any related administrative concessions affect the appropriate forum, early indications suggest that the 2026 BOI guidance does not alter court jurisdiction, but the administrative status of the promoted entity may be relevant to provisional remedies or enforcement strategy.

Limitation periods (prescription) vary by claim type under the Civil and Commercial Code. Contract claims generally carry a ten-year limitation period, while tort claims typically prescribe within one year of the date the injured party became aware of the tortious act and the identity of the tortfeasor. Specific commercial obligations may have shorter periods, counsel should verify the applicable window before issuing proceedings.

Step-by-Step Commercial Suit Procedure in Thailand

The following numbered steps set out the commercial suit procedure from initiation to enforcement. The timeline table below summarises each stage, the responsible party, and typical duration ranges observed in practice.

Step 1, Pre-Action Assessment and Evidence Preservation

Before filing, claimant counsel should carry out a structured pre-action assessment. This includes: reviewing the contract and identifying the cause of action; confirming the applicable limitation period has not expired; identifying assets available for enforcement; and evaluating whether an arbitration clause diverts the claim to arbitral proceedings.

A formal demand letter (หนังสือทวงถาม) should be issued to the opposing party. While not a statutory prerequisite in most commercial matters, a demand letter establishes the claimant’s good faith, may trigger interest accrual, and frequently prompts settlement negotiations.

Equally critical at this stage is evidence preservation. Claimant counsel should secure all relevant documents, contracts, correspondence, invoices, payment records and digital communications. For electronic evidence, forensic imaging, hash-value certification and metadata preservation are recommended. If there is a risk the defendant will dissipate assets, this is the point to prepare an application for provisional measures under the Civil Procedure Code, including temporary attachment of property or injunctive relief.

Step 2, File the Plaint (คำฟ้อง) and Pay the Filing Fee

To file a commercial claim in Thailand, the claimant submits a written plaint (kham fong / คำฟ้อง) to the court registry. The plaint must be drafted in Thai and must contain: the names and addresses of all parties; a statement of the facts constituting the cause of action; the relief sought (including quantified damages); and a list of supporting evidence. Foreign-language documents attached to the plaint must be accompanied by certified Thai translations.

Upon filing, the claimant pays the court filing fee. The fee is calculated as a percentage of the claimed amount, and is subject to a statutory cap. The court clerk issues a case number and dockets the matter. Filing may be completed in person at the court registry; the Office of the Judiciary has also expanded e-filing capabilities across certain courts, and claimants should confirm availability with the specific court.

Step 3, Service of Process and the Defendant’s Response

Once the court accepts the plaint, it orders service of the summons and a copy of the plaint on the defendant. Service is normally effected by a court bailiff at the defendant’s registered address. Where the defendant is located outside Thailand, service must comply with any applicable bilateral treaty or, in the absence of a treaty, be effected through diplomatic channels, a process that can extend the timeline significantly.

After service, the defendant has a prescribed period to file a statement of defence (kham hai kan / คำให้การ). This period is set by the Civil Procedure Code and is typically in the range of 15 to 30 days, though the court may grant extensions for cause. If the defendant fails to file a defence within the allotted time, the claimant may apply for a default judgment.

Step 4, Court-Ordered Mediation and Conciliation

Thai courts routinely order compulsory conciliation early in proceedings. The court appoints a conciliator, often a judge or experienced mediator, who facilitates settlement discussions between the parties. Conciliation sessions typically take place within 30 to 90 days of the close of pleadings. If the parties reach agreement, the court records a compromise judgment with the force of a final order. If conciliation fails, the case proceeds to the evidentiary stage.

Participation in conciliation is mandatory, but neither party is compelled to settle. Industry observers note that Thai courts treat conciliation as a genuine opportunity to resolve disputes efficiently, and a significant proportion of commercial cases settle at this stage.

Step 5, Evidence Stage: Witnesses, Documents and Experts

Following the close of conciliation, the court sets dates for the examination of witnesses and submission of documentary evidence. Each party submits its witness list and evidence bundle. Witnesses give testimony orally and are subject to cross-examination. The court may also appoint or permit expert witnesses in matters requiring specialised knowledge, valuations, technical assessments, accounting analyses and forensic reports are common in commercial suits.

Subpoenas may be issued to compel the attendance of witnesses or the production of documents. Digital evidence, emails, server logs, electronic transaction records, is admissible provided its authenticity and chain of custody can be demonstrated. Preparing a comprehensive evidence preservation report at the pre-action stage (Step 1) pays dividends here.

Step 6, Trial, Judgment and Appeals

After the evidentiary hearings conclude, the court delivers its judgment. First-instance judgments in straightforward commercial matters are typically rendered within 6 to 18 months of filing, though complex, multi-party or high-value disputes may take longer.

Either party may appeal the first-instance judgment to the Court of Appeal (ศาลอุทธรณ์) within the statutory deadline prescribed by the Civil Procedure Code. A further appeal on points of law to the Supreme Court (ศาลฎีกา) is possible, subject to leave requirements. Each appellate level may add 6 to 24 months. Claimants should factor appeal risk into their overall commercial litigation procedure in Thailand timeline and cost planning.

Step 7, Enforcement of Judgments

Once a judgment becomes final, the successful party applies to the Legal Execution Department (กรมบังคับคดี) for enforcement. Enforcement measures include seizure and sale of the debtor’s movable and immovable property, garnishment of bank accounts and receivables, and other execution steps authorised by the Civil Procedure Code.

Thailand does not recognise or enforce foreign court judgments directly, there is no reciprocal enforcement treaty framework. A foreign judgment must instead be re-litigated as a new action before a Thai court, with the foreign judgment tendered as evidence. By contrast, foreign arbitral awards are enforceable under the Thai Arbitration Act, which gives effect to the New York Convention. This distinction is a critical consideration for foreign claimants planning their dispute-resolution strategy.

Documents Needed for a Commercial Lawsuit in Thailand

The following table sets out the core documents required to file and prosecute a commercial claim. Foreign claimants should pay particular attention to legalisation and translation requirements, which are affected by Thailand’s 2026 Apostille Convention accession steps.

Foreign claimants should allow additional lead time, typically two to six weeks, for the legalisation or apostille process, depending on the issuing country’s procedures. Incomplete or improperly authenticated documents are among the most common causes of delay in cross-border commercial proceedings.

Thailand Commercial Court Timeline and Key Deadlines

Managing deadlines is fundamental to the commercial litigation procedure in Thailand. Missing a statutory deadline can result in loss of rights, default judgment or dismissal. The following deadlines and time-sensitive obligations require particular attention:

Immediate actions upon deciding to litigate should include: issuing a litigation-hold notice to preserve internal evidence; applying for provisional measures if asset dissipation is a risk; reviewing any arbitration or forum-selection clause; and instructing Thai counsel to run a preliminary jurisdictional and limitation-period check.

Costs of a Commercial Lawsuit in Thailand

The table below sets out the principal cost categories for a commercial suit. All figures are practice-range estimates and should be confirmed with the court registry and instructed counsel before budgeting.

Lenders and investors should also consider: ring-fencing litigation-cost escrow early in the process; whether the underlying transaction documents provide for recovery of legal costs; and VAT and withholding-tax treatment of counsel fees and recovered costs. A detailed cost-planning exercise with instructed counsel at the pre-action stage will avoid budget surprises and inform settlement decision-making.

What Changes in 2026: BOI, Apostille and Practice Updates

Three developments in 2026 carry practical consequences for the commercial litigation procedure in Thailand:

BOI 2026 Guidance

The Board of Investment has published updated announcements and guidance for promoted companies in 2026, including revisions to investment promotion measures and administrative procedures. While the BOI’s remit is investment promotion rather than court procedure, the administrative status of a BOI-promoted entity, including its permitted activities, foreign-ownership structure and reporting obligations, can be relevant to jurisdiction, standing and the availability of certain remedies. Claimants and defendants with BOI promotion certificates should confirm with counsel whether any 2026 BOI changes affect their litigation strategy.

Thailand’s Accession to the Hague Apostille Convention

The Thai Cabinet approved Thailand’s accession to the Hague Convention Abolishing the Requirement of Legalisation for Foreign Public Documents (the “Apostille Convention”) in December 2025. The Ministry of Foreign Affairs has been progressing the deposit and entry procedures in 2026. Once accession takes effect, public documents issued in Apostille Convention member states, including corporate certificates, notarised powers of attorney and court documents, can be authenticated with a single apostille stamp rather than undergoing the full consular legalisation chain. The likely practical effect will be a reduction in document-preparation time and cost for foreign claimants.

During the transitional period, litigants should verify with the MFA’s Department of Consular Affairs whether apostille authentication is yet accepted by Thai courts or whether the traditional legalisation process remains required. Early indications suggest that the MFA has published guidance on its transition timeline.

Court Digitisation and E-Filing

The Office of the Judiciary has continued expanding electronic filing and case-management systems across the Courts of Justice. Claimants should confirm with the specific court whether e-filing is available for their case type and division. Where available, e-filing can reduce administrative delays and simplify document submission, particularly for parties located outside Bangkok.

Common Pitfalls and How to Avoid Them

• Expired limitation period. Failing to verify the applicable prescription period before issuing a demand letter is one of the most costly errors. Different claim types carry different periods under the Civil and Commercial Code. Instruct counsel to confirm the limitation window as the first step in any pre-action assessment.
• Incomplete or improperly authenticated documents. Foreign-origin documents that are not notarised, legalised (or apostilled) and translated into Thai will be rejected or challenged. Allow at least two to six weeks for the authentication process and build this into the litigation timetable.
• Failure to preserve electronic evidence. Deletion of emails, chat logs or server data, whether accidental or by the opposing party, can be fatal to a claim. Issue a litigation-hold notice immediately upon contemplation of proceedings and engage forensic-preservation specialists for critical digital evidence.
• Inadequate service abroad. Serving a defendant outside Thailand through informal channels risks the service being challenged and set aside. Ensure service complies with any applicable bilateral treaty or is effected through diplomatic channels as required by the Civil Procedure Code.
• Underestimating provisional remedy needs. By the time a judgment is obtained, the defendant may have moved or dissipated assets. Assess the need for temporary attachment, injunctive relief or freezing orders at the pre-action stage, not after filing.
• Ignoring arbitration clauses. If the underlying contract contains a valid arbitration clause, filing a court action may result in the court staying proceedings and referring the dispute to arbitration. Review the dispute-resolution clause before committing to a litigation strategy.

As a practical checklist for the first 72 hours after a dispute arises: instruct counsel to confirm jurisdiction and limitation; issue a litigation hold on all relevant documents and data; assess whether provisional measures or interim relief are needed; review the dispute-resolution clause for arbitration or forum-selection provisions; and begin compiling the documents listed in the table above.

Sources

1. Office of the Judiciary, Courts of Justice, Thailand
2. Office of the Council of State (KRISDIKA), Official Legislation Repository
3. Royal Thai Government Gazette (Ratchakitcha)
4. Board of Investment of Thailand (BOI)
5. Ministry of Foreign Affairs, Apostille Convention Accession Notice
6. Hague Conference on Private International Law (HCCH)