According to the Customs Act, it is necessary to keep the declared or submitted materials if the prices, tax payment, import & export, return, warehousing, and taking out of bonded goods and bonded transportation declaration are reported or an M/F is submitted.

According to Article 12 of the Customs Act and Article 3 of its Enforcement Decree, below are the documents to be retained and their retention periods. It is possible to transmit and keep the materials in electronic means such as microfilm, optical disc, etc.

Documents to be retainedRetention period
- Certificate of import declaration
- Contract for import transaction or substitute document
- Contract for the transaction of intellectual property rights or substitute document
- Materials on the decision of price of imported goods
5 years from the date of acceptance of the declaration
- Certificate of export declaration
- Certificate of export return declaration
- Materials on the decision of the price of exported or returned goods
- Contract for an export transaction or return transaction or substitute - document
3 years from the date of acceptance of the declaration
- Materials on warehousing and taking out of bonded cargo
- Materials on the shipping list
- Materials on bonded transportation
2 years from the date of acceptance of the declaration

If a person imports goods from the other person with a special relationship in a foreign country, it is necessary to retain the following materials additionally and submit them at the time of tax amount screening:
(Article 37-4 of the Customs Act and Article 31-5 of its Enforcement Decree)

Documents to be submitted
  1. The current status of mutual investments among persons in special relationships;
  2. IInternal materials for price decision such as a detailed statement of calculation of the price of imported goods and materials on the international transaction price policy
  3. A contract for purchasing imported goods and a contract for sharing the cost price;
  4. A contract for franchise fees, royalties for technology transfer, fees, etc.;
  5. A contract for supporting business and management, such as advertising and sales promotion;
  6. Standard and method of accounting management related to the transaction concerned
  7. Audit report and annual report of a person with a special relationship living abroad
  8. Details of payment and receipt of overseas price and evidentiary materials
  9. Consolidated and individual corporate report according to Article 21-2 of the Enforcement Decree of the Adjustment of International Taxes Act
  10. Other data necessary for the assessment of dutiable value on imported goods.

Those who do not retain declaration documents or do not submit the requested materials are subject to punishment.