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June 2, 2023

Customs Post-assessment Dispute Mechanisms: Challenging Official Duty Assessments

Efficiency and predictability in the global supply chain are critical for business operations. Whether involved in manufacturing, distribution, logistics, or even in the provision of services, most business operators rely upon problem-free customs clearance in the countries in which they operate. If customs disputes do arise and are not effectively addressed, they can have a profound impact on operations, delaying delivery, creating potential civil and criminal liabilities, or even resulting in the seizure of imported goods.

Often, importers or their agents can become complacent, particularly where there has been a period of months or even years of customs clearance without encountering any issues. However, disputes can arise, often relating to origin of goods, classification, and duty assessment. When not addressed early in the dispute process or through settlement, a dispute can escalate, leading to issuance of official letters of assessment by customs authorities. Once Thai customs has issued such a formal letter of assessment to an importer, discretion in settlement is gone and only the full value of the duty assessment can be accepted. At this stage, the only legal avenue for challenge is to accept the duty assessment or to litigate. This article addresses post-assessment litigation options to challenge official customs duty assessments.

Customs Board of Appeals

Once an official assessment is made, an importer has the right to seek a formal appeal of the customs assessment with the Customs Board of Appeals or to otherwise make payment of the full assessment within 30 days of the date it received the assessment. Extensions of time are not permitted. With few exceptions, the right to appeal does not allow the importer to defer an assessed duty payment. This means that the importer must post security for the assessed duty at the time of filing the appeal.

This essentially means that an importer has a tight timeframe in which to prepare and file an appeal and security. Since many customs disputes involve complex issues of goods classification, application of rules of origin, and exemptions under free trade agreements, it is imperative the importers and counsel work in advance of formal assessment so that they are prepared to file appeals within the 30 day period.

The Thai Customs Act provides that the Board of Appeals has 180 days to complete the appellate procedure. The Board of Appeals has the opportunity to extend the procedure for up to 90 days, but only if there is necessary cause. Thereafter, if the appellate procedure cannot be completed within the original or extended time period, an importer has the right to consider withdrawing the appeal and filing a lawsuit in the applicable court.

The Board of Appeals and its Appeal Committee have the right to appoint a subcommittee to perform any entrusted duty. The committee or subcommittee can issue a summons to the appellant or request any person to give an oral statement or submit any documentation concerning the appeal. A Customs Board of Appeals ruling is final, made in writing, and submitted to the appellant. If the appellant is dissatisfied with the ruling, it has the right to file a lawsuit in court within thirty days of receiving the ruling.

Filing Claims with the Court

Where there has been an official duty assessment by Thai customs, an importer, if it wishes to bypass the Customs Board of Appeals process, has the right to file a direct claim with the court of jurisdiction for a customs dispute. This is typically the specialized Tax Court. Alternatively, an importer can await the conclusion of the Customs Board of Appeals process before exercising its right to file a claim with the applicable court. This is a decision that each importer needs to consider on its own, but in most cases the initial decision will be to file appeals with the Board of Appeals as a first dispute resolution option, and only if the ruling is unfavorable will a party then consider further filings to the court. This is a decision made on a case-by-case basis and there is no set formula on what strategy to employ, but there is a general understanding that the Board of Appeals has more expertise than the courts, particularly in complex customs disputes.

As is the case for Board of Appeals reviews, a post of security for the assessment is required during the trial court process. Court proceedings will proceed until issuance of the court judgment. There is a further right to consider an appeal to the Supreme Court, which under current rules has the right to exercise its discretion on whether to accept the appeal. If the appeal is not accepted, then the court judgment will be final and no further avenues of challenge will be possible.


Customs clearance and valuation are important parts of the global supply chain. In most cases, goods move freely and without negative effects. However, when customs conflicts do arise, it is critical that importers and their counsel act to assess and advocate in defense of claims. Where necessary, a well-planned and thorough defense, whether through the customs appeal process or through the courts, can reduce or otherwise eliminate assessed customs liabilities. In fact, a favorable ruling may even set a standard that reduces the likelihood of similar disputes in the future.