ISF Filing: The Complete Guide for US Importers (2026)

Facts verified against CBP.gov and 19 CFR Part 149 on July 7, 2026.

Every shipment that arrives in the United States by ocean vessel requires an Importer Security Filing, known as the ISF or the 10+2. The ISF importer must transmit ten data elements to US Customs and Border Protection no later than 24 hours before the cargo is loaded onto the vessel at the foreign port. Miss the deadline, skip the filing, or file inaccurate data, and CBP can assess liquidated damages of $5,000 per violation. This guide covers who files, what goes in the filing, when it is due, what it costs, and how to stay penalized-free on every shipment.

The Importer Security Filing Applies to Every Ocean Shipment

The ISF is a CBP advance cargo data requirement created under the SAFE Port Act and enforced since January 26, 2009. The rule lives at 19 CFR Part 149 and applies to all cargo arriving in the United States by vessel. It does not apply to air freight, truck shipments, or rail shipments, and it covers both full container loads and less than container load freight. If your goods travel by ocean into a US port, ISF applies regardless of shipment size or value.

The requirement comes in two forms. The ISF-10 is the full filing for goods entering US commerce or destined for a Foreign Trade Zone, and it is the responsibility of the ISF importer, meaning the party causing the goods to arrive in the United States. The ISF-5 is a reduced five-element filing for cargo that touches a US port without entering commerce, covering freight remaining on board, immediate exportation, and transportation and exportation movements. The name 10+2 reflects the split of responsibility: the importer supplies ten elements, and the ocean carrier separately supplies two, the vessel stow plan and container status messages. Carrier elements are never the importer's problem, so this guide focuses on the ten that are.

The ISF Deadline Is 24 Hours Before Vessel Loading

The ISF must be accepted by CBP no later than 24 hours before the cargo is laden aboard the vessel at the foreign port. The clock runs from loading, not from sailing and not from arrival in the United States. In practice, ocean carriers set documentation cutoffs earlier than the loading window, so the working target for your data should be several days before departure.

The rule builds in two kinds of flexibility. First, two elements, the container stuffing location and the consolidator, may be submitted after the initial filing but no later than 24 hours before the vessel arrives at its first US port. Second, four elements, the manufacturer, country of origin, HTSUS number, and ship-to party, may initially be filed based on the best information available at the time, then updated as facts firm up. An ISF can be amended up to the moment the cargo arrives at the first US port, and only the party that originally filed it may update or delete it. If your supplier changes, your goods are sold in transit, or your delivery warehouse moves, amend before arrival rather than hoping the mismatch goes unnoticed. CBP compares the ISF against the entry data, and discrepancies raise flags.

The 10 Data Elements Every ISF-10 Must Contain

The ten importer elements identify every party and place in the supply chain, from the factory floor to the first US delivery point. Collect them when the purchase order is issued, not when the container is ready to ship.

1. Seller: name and address of the party that sold the goods, or the owner if there is no sale

2. Buyer: name and address of the party purchasing the goods, or the owner if there is no sale

3. Importer of record number: the IRS EIN, SSN, or CBP-assigned number of the party liable for duties

4. Consignee number: the IRS number of the US party on whose account the merchandise ships

5. Manufacturer or supplier: name and address of the entity that produced the goods

6. Ship-to party: the first US location scheduled to receive the goods after release physically

7. Country of origin: the country of manufacture, matching what will be declared at entry

8. HTSUS number: the tariff classification to at least the six-digit level

9. Container stuffing location: the physical address where the container was stuffed

10. Consolidator: the party that stuffed the container or arranged the stuffing

Two structural rules trip up first-time filers. The manufacturer, country of origin, and HTSUS number must be linked at the line-item level, so a shipment with three suppliers requires three linked lines, not three lists. And the filing must carry the bill of lading number at the house bill level, because CBP uses it to tie the ISF to the carrier's manifest and later to your entry. An ISF with the wrong bill number is functionally an ISF that was never filed.

ISF-5 Covers Cargo That Never Enters US Commerce

Freight remaining on board a vessel that calls at a US port, and cargo moving under immediate exportation or transportation and exportation bonds, requires only five elements: the booking party, the foreign port of unlading, the place of delivery, the ship-to party, and the commodity HTSUS number. If a shipment planned as a consumption entry converts to an in-bond export movement, the filing converts with it. Most commercial importers reading this will only ever file the ISF-10, but knowing the ISF-5 exists prevents confusion when a forwarder mentions it on transshipped freight.

ISF Penalties Reach $5,000 Per Violation

CBP enforces the ISF through liquidated damages of $5,000 per violation, capped at $10,000 per ISF filing. Violations include failing to file, filing late, filing inaccurate data, and failing to update a filing when the facts change before arrival. The money is only part of the exposure. Late or missing ISFs raise the shipment's score in CBP's Automated Targeting System, which invites holds and intensive examinations at the importer's expense, and demurrage accumulates while the container sits. In serious cases CBP issues a Do Not Load order and the container never leaves the foreign port.

Responsibility cannot be delegated away. The ISF importer remains legally responsible for a timely, accurate, and complete filing even when a customs broker or freight forwarder transmits it. If your agent files late, the liquidated damages claim lands on the bond posted for the ISF. CBP does weigh mitigation factors, including compliance history, whether the violation was isolated, and corrective action taken, and first-time violators with clean records sometimes receive a warning instead of a claim. Building a business on the hope of mitigation is not a compliance strategy.

A Customs Bond Is Required to File an ISF

Every ISF must be secured by a bond. If you hold a continuous customs bond for your entries, it already covers your ISF obligations and nothing more is needed. Importers without a continuous bond purchase a single transaction ISF bond for each filing, a separate instrument from the single entry bond. Importers moving three or more ocean shipments a year almost always come out ahead with a continuous bond, which covers ISF and entry obligations across all ports for twelve months. For a full walkthrough of bonds and the rest of the import process, see our guide to importing into the USA.

ISF Filing in 2026: More First-Time Importers Face the Requirement

The suspension of the de minimis exemption pushed a generation of e-commerce businesses out of duty-free parcel streams and into consolidated ocean freight, and with the permanent repeal taking effect on July 1, 2027, that migration is accelerating. Many of these businesses are filing formal entries for the first time, and the ISF is the compliance step they most often discover too late, because it comes due before the vessel sails rather than when the goods arrive. If 2026 is the year your business shifts from air parcels to ocean containers, put ISF at the top of the checklist, not the bottom.

How to File an ISF Step by Step

11. Collect the ten data elements at purchase order time and confirm them with your supplier and forwarder in one standard template

12. Verify the HTSUS classification before filing, because the ISF code must reconcile with the code used at entry

13. Confirm bond coverage: continuous bond on file, or a single transaction ISF bond arranged for the shipment

14. Transmit the filing through a licensed customs broker's ABI connection to ACE, referencing the house bill of lading number

15. Monitor the CBP response: accepted, accepted with warnings, or rejected. A rejected ISF must be corrected and refiled before the 24-hour cutoff

16. Amend promptly if any element changes before the vessel arrives at the first US port

Clearit USA files your ISF for a flat $35 through our online platform. Upload your shipment details, and our licensed brokers transmit, monitor, and amend the filing so your container loads on schedule and clears without surprises. Get started on our ISF filing service page.

Frequently Asked Questions About ISF Filing

Do I need to file an ISF for air freight?

No. The Importer Security Filing applies only to cargo arriving in the United States by ocean vessel. Air, truck, and rail shipments are exempt from ISF, although air cargo is covered by a separate advance data program. If any leg of your import moves by ocean into a US port, ISF applies.

When is the ISF due?

The ISF must be accepted by CBP no later than 24 hours before your cargo is loaded onto the vessel at the foreign port. The clock runs from loading, not from sailing or arrival. Two elements, the container stuffing location and the consolidator, may follow later but no later than 24 hours before arrival at the first US port.

How much does an ISF filing cost?

The filing itself is inexpensive. Clearit USA files your ISF for a flat $35. If you do not hold a continuous customs bond, you will also need a single transaction ISF bond for the shipment. The real cost of ISF is non-compliance, where liquidated damages run $5,000 per violation.

What happens if the ISF is filed late?

CBP may assess liquidated damages of $5,000 per violation, up to $10,000 per ISF. Late or missing filings also raise your shipment's risk score, which can trigger holds and examinations at your expense, and in serious cases a Do Not Load order that stops the container at the foreign port.

Can I file the ISF myself?

Yes, a self-filing importer can transmit the ISF through CBP's ACE portal, but most importers use a licensed customs broker with an ABI connection because rejected or inaccurate filings carry the same penalty exposure as late ones. Whoever transmits it, you remain legally responsible as the ISF importer.