If Korea-Vietnam FTA rates were mistakenly applied despite having a Korea-ASEAN FTA Certificate of Origin for Vietnam imports, can I retroactively apply the lower rate within 1 year of clearance to refund the tariff difference? Released

If you have a valid Korea-ASEAN FTA Certificate of Origin when importing goods from Vietnam but mistakenly applied the Korea-Vietnam FTA preferential tariff rate during the import declaration process, it is entirely possible to retroactively apply the Korea-ASEAN FTA preferential tariff to receive a refund of the tariff difference for cost savings. This is a right granted to importers based on the Domestic Customs Act and the Special Act on the Customs Act for the Implementation of FTAs.

Specifically, you can apply for retroactive application to the Korea Customs Service or the head of a customs office within one year from the date of import declaration acceptance. This process goes beyond simply receiving a refund of the tariff difference; it includes canceling the Korea-Vietnam FTA preferential tariff application made during the initial declaration and revising the tax amount by newly applying the Korea-ASEAN FTA preferential tariff rate that should have been applied.

The procedure is as follows. First, the importer must proceed with an amended return (or request for rectification) to correct the existing import declaration details. During this process, the original (or a valid copy) of the Korea-ASEAN FTA Certificate of Origin must be submitted, and it must be proven that the goods meet the Rules of Origin of the Korea-ASEAN FTA. Customs will conduct a review based on the submitted Certificate of Origin and other related documents. If there are no issues, they will recalculate the tariff amount by applying the Korea-ASEAN FTA preferential tariff rate and refund the difference from the tariff already paid.

This retroactive application system was established to provide relief in cases where an importer has a valid Certificate of Origin but failed to apply a more favorable preferential tariff rate due to administrative errors, system errors, or a lack of tariff rate comparison. In particular, since Korea has signed two separate FTAs with Vietnam—the Korea-ASEAN FTA and the Korea-Vietnam FTA—tariff rates for the same item may vary by agreement. Therefore, it is important to select the most favorable preferential tariff upon importation. In cases like this where an error has occurred, the tariff reduction effect can be maximized by applying the correct preferential tariff retroactively.

When applying for retroactive application, it is essential to prepare accurate documents and thoroughly verify whether the Rules of Origin are met. You must carefully review whether the Korea-ASEAN FTA Certificate of Origin was validly issued, whether the expiration date has passed, and whether the HS Code and Rules of Origin (ROO) are clearly stated. Additionally, all requirements for FTA application, such as the direct transport principle, must be met. For complex matters or those involving large tariff amounts, you can receive faster and more accurate tariff refunds by proceeding with the assistance of a customs broker.