Customs Audit Procedure

Which step are you at?

Select your current step and the content for that step will appear below.

1. 1Selection of audit targets
2. 2Advance notice of customs audit
3. 3Start of audit and participation of attorney or customs broker
4. 4Examination of books and documents, and temporary custody
5. 5Notice of audit results
6. 6Pre-assessment notice and request for pre-assessment review
7. 7Payment notice and payment
8. 8Objection, request for review, request for adjudication
9. 9Administrative lawsuit

• Basic step
• Additional action / option
• Rejection / objection
• End of procedure

Time required

The on-site audit period is in principle within 20 days (extendable if there is a reason); the result notice comes within 20 days after the audit ends; it takes longer if you go on to the objection procedure

Cost

The Customs Act has no provision for fees for a customs audit or for an objection or request for review; customs broker and attorney fees are separate; stamp fees for an administrative lawsuit are separate

Procedure guide

Read from start to finish in order. Red text marks deadlines set by law.

1. 1

   The head of the customs office selects customs audit targets through regular selection or ad hoc selection (Customs Act §110-3, Enforcement Decree §135-3). Grounds for regular selection include a taxpayer who has not been audited for the last 4 years or more. Because it is hard to know in advance whether you will be selected, organizing evidence such as import declarations, contracts and remittance records by transaction in ordinary times is a good way to prepare.

   Current step
2. 2

   Customs sends an advance notice stating the audit target and reason, etc. 20 days before the audit starts (7 days before for a re-audit) (§114(1)). Before the amendment effective January 1, 2026, it was 15 days before, so look at the notice timing based on the current 20 days. If there are circumstances such as illness, a long business trip or a disaster, you can apply to postpone the audit (§114(2), Enforcement Decree §140), and customs tells you whether it is approved before the audit begins. If it is a customs offense case or there is a risk of destruction of evidence, the audit may start without notice. If notice was omitted because of a risk of destruction of evidence, you receive the notice items and the reason for no notice in writing on the first day of the audit (§114(3)).

3. 3

   The auditor hands over the Taxpayer Rights Charter, explains the reason for the audit, the audit period and the remedy procedures, and then starts the audit (§110(2)). The company can have an attorney or customs broker take part in the audit (§112). Answers given early in the audit carry through to the result notice and the objection stage, so it is better to have them with you from the start. If the audit scope changes, you must receive the changes and reasons in writing (§114(4)), and re-auditing the same matter already audited is in principle prohibited (§111(2)).

4. 4

   The on-site audit period is within 20 days; if there is a reason it is extended by up to 20 days, and extending 2 or more times requires approval from the Commissioner of the Korea Customs Service (Enforcement Decree §139-2). The auditor cannot take books at will and may only keep them in temporary custody with the company's consent (§114-2(1)(2)). Books in temporary custody cannot be kept for more than 14 days from the date return is requested (extendable once by up to 14 days after deliberation by the Taxpayer Protection Committee, §114-2(4)). If suspicion of a customs offense emerges during the audit, it turns into a customs offense investigation, which can lead to a notice of disposition (§311) or an accusation. So avoid hiding books or creating new evidence.

5. 5

   When the audit ends, the results are notified in writing within 20 days after the audit ends (§115). Review the additional collection and grounds stated in the notice right away and decide whether there is anything to dispute. This is because the deadline for the next step, the pre-assessment review, is short. In cases such as a notice of disposition or accusation, or a business that has closed, the result notice may be omitted as an exception.

6. 6

   When customs gives a pre-assessment notice, file a request for a pre-assessment review with the head of the customs office (or with the Commissioner of the Korea Customs Service, for example where a change in the Commissioner's official interpretation or a new interpretation is needed) within 30 days of receiving the notice (§118(1)(2)). Customs decides within 30 days of receiving the request (§118(3)). If you do not dispute the notice, you can also apply for an early correction to have the tax amount fixed right away (§118(5)).

7. 7

   When you receive a payment notice, pay the tax within 15 days of receipt (§9(1)2). Because the deadline is short, it is safer to prepare the funds for payment from the pre-assessment review stage. The date you receive the notice is the starting point of the 90-day objection period, so record the date.

8. 8

   To dispute the assessed tax, file an objection (optional) with the head of the customs office, or a request for review with the Commissioner of the Korea Customs Service (§121) or a request for adjudication with the Tax Tribunal (§131), within 90 days of the date you learned of the disposition (the date you received the notice). If you went through an objection, file within another 90 days of receiving its decision notice (§121(2)). You cannot file both a request for review and a request for adjudication against the same disposition (§119(10)). If you still disagree with the decision, file an administrative lawsuit within 90 days of receiving the decision notice (§120(3)). This is a peremptory period and cannot be extended (§120(6)).

Frequently asked questions

Practical questions that come up right away in this procedure.

QHow many days in advance does a customs audit notice come?

The current Customs Act requires notice 20 days before the audit starts (7 days before for a re-audit). Before the amendment effective January 1, 2026, it was 15 days before.So guidance materials stating 15 days follow the pre-amendment rule. If it is a customs offense case or there is a risk of destruction of evidence, the audit may start without notice.If notice was omitted because of a risk of destruction of evidence, you receive a written document on the first day of the audit. It states the notice items and the reason you were not told in advance.

QCan I postpone the audit date?

Yes, you can apply for a postponement if there is a ground such as illness, a long business trip, a fire or disaster, or seizure of the books. Customs tells you whether it is approved before the audit begins. No application deadline is set as a date in the laws or the Korea Customs Service directive.However, approval must be decided before the audit begins. So when you receive the notice, it is best to organize the reason for postponement and the supporting materials and apply right away.

QCan I have a customs broker or attorney take part in the audit?

Yes, you can. The Customs Act allows you to have an attorney or licensed customs broker take part in a customs audit.If the issues are complex or the audit may turn into a customs offense investigation, it is better to respond together from the start. This is because answers given early in the audit carry through to the result notice and the objection stage.

QCustoms took our books. When can we get them back?

Customs cannot keep them for more than 14 days from the date you request their return. If there is no obstacle to the audit, they must be returned immediately.After deliberation by the Taxpayer Protection Committee, they can be kept once more, for up to 14 days. Keep a list and copies of the books you handed over so you can check them when they are returned and keep your business running.

QI received a payment notice. By when do I have to pay?

You must pay within 15 days of receiving the payment notice. If you want to dispute before the notice, you must act at the earlier stage.That is, file a request for a pre-assessment review (a request for review before the notice) within 30 days of receiving the pre-assessment notice. So it is best to decide whether to respond at the notice stage.

QWhere do I file a customs objection?

File an objection (optional) with the head of the customs office, or a request for review with the Commissioner of the Korea Customs Service or a request for adjudication with the Tax Tribunal. The deadline is 90 days from the date you learned of the disposition (the date you received the notice).You cannot file both a request for review and a request for adjudication against the same disposition, so choose one. You can see the detailed flow in "Tax Appeal Procedure."