US import filings
ISF 10+2 filing for ocean freight from Korea
Every container sailing from Busan, Incheon or Gwangyang to a US port needs an Importer Security Filing before it is loaded in Korea, not before it arrives in the US. The US importer files it, but most of the data comes from the Korean seller and the forwarder. Here is what the filing contains, who supplies each piece, and how to keep it on time.
Not customs advice. This page summarizes the Importer Security Filing rule in 19 CFR Part 149 as published by US Customs and Border Protection (CBP). Confirm current requirements on CBP's ISF page or with a licensed customs broker before you rely on it.
What ISF is, and what it is not
The Importer Security Filing, usually called ISF or "10+2", is a CBP requirement for cargo arriving in the United States by vessel. It took effect in January 2009. The name describes its two halves: the importer transmits ten data elements, and the ocean carrier transmits two more. CBP uses the data to assess the security risk of a container before it leaves the foreign port.
ISF is often confused with two other things:
- The carrier's manifest (AMS). The ocean carrier or NVOCC must also send cargo manifest data to CBP 24 hours before loading. That is the carrier's filing, under a separate rule. It does not replace the ISF.
- The customs entry. ISF is not an entry and does not pay duty. The importer of record still files entry and entry summary when the goods arrive, as described in customs and documents on the Korea–US lane.
Air cargo is not subject to ISF. Air shipments have their own advance electronic data program, which the airline and forwarder handle.
The deadline: 24 hours before loading in Korea
For cargo destined to be unladen in the US, the ISF must be transmitted at least 24 hours before the cargo is laden aboard the vessel at the foreign port. For a Korea shipment, the clock runs against loading in Busan (or wherever the container is first loaded for the US voyage), not against the vessel's arrival in Los Angeles or Savannah.
In practice, many forwarders ask for ISF data before the container yard cut-off, because the loading time is not always known precisely and a transshipment through another Asian hub can change which vessel counts. If your cargo moves as LCL, the consolidator's cut-off is usually earlier still; see FCL vs LCL from Korea.
The ten importer elements, and where each comes from
| ISF element | What it means | Usually supplied by |
|---|---|---|
| 1. Seller (owner) | The last known entity by whom the goods are sold or agreed to be sold | Korean exporter / purchase order |
| 2. Buyer (owner) | The last known entity to whom the goods are sold | US importer |
| 3. Importer of record number | IRS, EIN, SSN or CBP-assigned number of the importer of record | US importer |
| 4. Consignee number(s) | Identification number of the party receiving the goods in the US | US importer |
| 5. Manufacturer (or supplier) | The entity that last manufactured, assembled or produced the goods | Korean exporter |
| 6. Ship-to party | The first deliver-to party scheduled to physically receive the goods after release | US importer |
| 7. Country of origin | Country of manufacture, production or growth | Korean exporter |
| 8. Commodity HTSUS number | US tariff number, at least to the six-digit level | Exporter's HS code, confirmed by the US broker |
| 9. Container stuffing location | Where the goods were stuffed into the container | Exporter or forwarder |
| 10. Consolidator (stuffer) | The party who stuffed the container or arranged for it | Exporter or forwarder |
The two carrier elements are the vessel stow plan and container status messages. The Korean exporter does not provide those.
CBP allows some flexibility for elements 9 and 10: they may be sent later than the rest, as early as possible and no later than 24 hours before the vessel arrives at a US port. The other eight still have to meet the pre-loading deadline. The ISF must also be updated if information changes before the vessel arrives.
Shipments that only pass through the US (freight remaining on board, immediate exportation, or transportation and exportation) use a shorter five-element ISF instead of the full ten.
A workable sequence for Korea exports
- Agree who files. The "ISF importer" is responsible, which is normally the US buyer or its broker. Under EXW or FOB terms the buyer's forwarder often files; under DDP the Korean seller may be acting as importer and must arrange it. Incoterms 2020 for Korea trade explains how the rule you choose shifts this work.
- Send the exporter data with the booking. Seller, manufacturer, country of origin, the six-digit HS code and the planned stuffing location can be sent as soon as the booking is confirmed.
- Confirm the HS code at six digits. Korea's 10-digit HSK code and the US 10-digit HTSUS number usually match only to six digits. Send six and let the US broker confirm the rest.
- Report stuffing details after loading the box. Once the container is packed, confirm where and by whom, especially for LCL, where the consolidator's CFS is the stuffing location.
- Get the ISF transaction number. Ask the filer to confirm acceptance before cut-off and keep the confirmation with the shipment record.
- Update if anything changes. A different manufacturer, split container or rolled booking can change the data. The filing must be amended.
Bonds and penalties
The ISF importer generally needs a customs bond that covers ISF obligations, either a continuous bond already used for entries or a single-transaction bond for the filing. CBP can assess liquidated damages for late, inaccurate or missing filings; CBP's published guidance sets these at up to $5,000 per violation. A missing ISF can also lead to holds, "do not load" messages and extra examinations, which cost time as well as money.
ISF checklist for Korean exporters
- Legal names and addresses of seller and manufacturer, exactly as on the commercial invoice
- Country of origin for each line item, including items sourced from outside Korea
- Six-digit HS code per line, consistent with the invoice and packing list
- Container stuffing address (your factory, a warehouse, or the forwarder's CFS)
- Name of the party that stuffed the container
- Booking number, bill of lading number and container number, so the filer can link the ISF to the manifest
Most ISF errors come from documents that disagree. The export shipping documents checklist covers how the invoice, packing list and bill of lading should line up.
Common questions
Does a Korean exporter have to file ISF?
Not usually. The ISF importer, normally the US buyer or its agent, is responsible. The Korean exporter's job is to provide accurate data early. If the exporter sells DDP and acts as the US importer, the obligation moves with it.
Is ISF needed for air freight from Incheon?
No. ISF applies to vessel cargo. Air cargo is covered by separate advance data requirements handled by the carrier and forwarder.
What if the ship leaves before the ISF is filed?
A late ISF can result in liquidated damages, holds and examinations when the cargo arrives. File as soon as the data is known, and do not treat the 24-hour rule as a target to meet at the last minute.
Does ISF change how much duty is paid?
No. Duty is determined at entry, based on classification, value, origin and the tariff measures in force at the time. Preferential treatment under the KORUS FTA is claimed at entry, not in the ISF.
Last reviewed 2026-09-17