An ISF filing is the Importer Security Filing that 19 CFR Part 149 requires for almost every shipment arriving in the United States by vessel, and its core data is due no later than 24 hours before the cargo is laden aboard the ship at the foreign port. The rule is known as 10+2 because the importer side transmits ten data elements and the ocean carrier transmits two more: a vessel stow plan and container status messages. CBP made the requirement enforceable on January 26, 2010, and it is enforced through the customs bond, at $5,000 in liquidated damages for each violation under 19 CFR 113.62(j).
The filing happens weeks before a customs entry exists, which is why it trips up importers who think of compliance as something that starts at the port. This guide covers the data CBP wants, who is legally responsible for sending it, the ISF-5 variant for cargo that is not being entered, the enforcement tools CBP uses, and how bonds and amendments work. Where the ISF sits in the full sequence of arrival, entry and entry summary is mapped in our guide to customs clearance procedures. Rules verified against the eCFR and CBP guidance as of November 13, 2026.
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The 10 Importer and 2 Carrier Data Elements Under 19 CFR 149.3
The importer side of the ISF consists of ten data elements listed in 19 CFR 149.3(a), reported for each good at the six-digit HTSUS level and at the lowest bill of lading level, which means the house bill when there is one. Three of them, the manufacturer or supplier, the country of origin and the HTSUS number, must be linked to one another line by line, so a container of mixed product from two factories needs two linked sets, not one header.
Most elements accept a name and address or a widely recognized commercial identification number. The HTSUS number must be given to at least six digits and may be given to ten; CBP can only reuse it for the entry if it is supplied at ten digits by the importer of record or its licensed customs broker. The importer of record number is the IRS number, EIN, SSN or CBP-assigned number of the party liable for duties, the same identity question covered in our explainer on the importer of record.
| # | Element | What CBP expects | Latest transmission |
|---|---|---|---|
| 1 | Seller | Last known entity that sold or agreed to sell the goods | 24 hours before lading at foreign port |
| 2 | Buyer | Last known entity to whom the goods are sold | 24 hours before lading |
| 3 | Importer of record number / FTZ applicant ID | IRS, EIN, SSN or CBP-assigned number of the liable party | 24 hours before lading |
| 4 | Consignee number(s) | Number of the US party on whose account goods are shipped | 24 hours before lading |
| 5 | Manufacturer (or supplier) | Party that last manufactures, assembles, produces or grows the goods | 24 hours before lading (flexible, update by 24 hours before arrival) |
| 6 | Ship to party | First party scheduled to physically receive the goods after release | 24 hours before lading (flexible) |
| 7 | Country of origin | Country of manufacture, production or growth under US rules | 24 hours before lading (flexible) |
| 8 | Commodity HTSUS number | Six digits minimum, up to ten | 24 hours before lading (flexible) |
| 9 | Container stuffing location | Where the goods were stuffed or made ship-ready | 24 hours before arrival in a US port |
| 10 | Consolidator (stuffer) | Party that stuffed the container or arranged it | 24 hours before arrival in a US port |
Who Files and the 24-Hour Vessel-Loading Deadline
The legal obligation to file sits with the ISF Importer, which 19 CFR 149.1(a) defines as the party causing the goods to arrive by vessel: the goods’ owner, purchaser, consignee, or an agent such as a licensed customs broker. The importer may hand the transmission to an agent, but liability for a late or wrong filing stays with the ISF Importer. For in-bond immediate exportation and transportation and exportation shipments, and for goods headed to a foreign trade zone, the party filing that in-bond or zone documentation may also act as ISF Importer.
Elements one through eight are due no later than 24 hours before the cargo is laden aboard the vessel at the foreign port, under 19 CFR 149.2(b). The container stuffing location and consolidator are due as early as possible and no later than 24 hours before arrival at a US port, or on lading when the voyage to the nearest US port is under 24 hours. The deadline runs from loading, not from sailing or booking.
Four elements are flexible under 149.2(f): manufacturer, ship-to party, country of origin and HTSUS number may be sent on the best data available, then updated with more precise data no later than 24 hours before arrival. CBP’s ISF FAQ (May 2023) lists a flexible filing not converted to a final (CT) transaction at least 24 hours before arrival as an inaccurate ISF, as is an ISF that does not match the bill of lading by then.
Mechanically, the ISF goes to CBP through ABI with a filer code or through the ocean manifest system with a SCAC. CBP’s FAQ confirms the filing agent does not have to be a licensed broker or located in the United States, and a foreign forwarder can file, unless the ISF is combined with the entry in a single Unified Entry transmission. That combined filing must be made by the importer itself or a licensed customs broker under 19 CFR 149.5(a), and CBP’s ACE Cargo Release guide adds three conditions: the importer of record and ISF Importer must be the same entity, the entry must cover the full manifested bill of lading quantity, and one bond must cover both transactions. Importers that run a high volume of ocean bookings usually track the clock in a system such as our ISF filing software; the regulation is indifferent to the tool, only to the timestamp.
What the carrier sends: the +2
The two carrier elements are not the importer’s to file. Under 19 CFR 4.7c the vessel operator must transmit a vessel stow plan no later than 48 hours after departure from the last foreign port, or before arrival for voyages under 48 hours. Under 19 CFR 4.7d, carriers transmit container status messages within 24 hours of entering the event in their tracking systems, but only for events they already record; the rule does not force a carrier to create messages it does not otherwise generate.
ISF-5 for FROB, IE and T&E Cargo
Cargo that arrives by vessel but is not being entered for consumption or admitted to a zone uses a shorter filing, commonly called ISF-5, with five elements under 19 CFR 149.3(b): booking party, foreign port of unlading, place of delivery, ship-to party and the six-digit HTSUS number. It covers three situations. Foreign cargo remaining on board (FROB) passes through a US port without being unladen for US delivery; immediate exportation (IE) and transportation and exportation (T&E) in-bond shipments are unladen in the United States but leave again without entering US commerce.
The filer and timing differ by case. For FROB the ISF Importer is the carrier or NVOCC, and the five elements are due before lading at the foreign port. For IE and T&E shipments the deadline is the same 24 hours before lading that applies to ISF-10. Goods destined for a foreign trade zone are not ISF-5 cargo: they file the full ten elements, with the zone applicant’s identification number in place of the importer of record number.
Plans change in transit. When a shipment originally filed as ISF-5 is instead going to be entered, CBP’s FAQ requires a new ISF-10 created with submission type 3 to replace the existing ISF-5, rather than an edit of the five-element filing. Bulk cargo that is exempt from the 24-hour cargo declaration is exempt from ISF entirely under 19 CFR 149.4, and exempt break bulk files 24 hours before arrival instead of before lading. Once bulk product is put in a container, CBP no longer treats it as bulk and the normal ISF applies.
Liquidated Damages, Holds and Do-Not-Load Messages
CBP enforces the ISF mainly through liquidated damages against the bond, at $5,000 for each violation under 19 CFR 113.62(j). Under the mitigation guidelines published in the Customs Bulletin on July 17, 2009, CBP’s FAQ describes the claim structure as $5,000 per late ISF, $5,000 per inaccurate ISF and $5,000 for the first inaccurate update. A claim can be cancelled in full when it was issued in error or with no fault on the importer’s side, such as a bill of lading mismatch caused by an ACE problem, and CBP reviews each case on its facts.
The second tool is operational. CBP’s FAQ tells non-compliant ISF Importers to expect delays in release while CBP analyzes and potentially examines the cargo, and importers with a history of ISF problems face more intensive examinations because CBP lacks the data to target in advance. A shipment that arrives with no ISF can sit under a hold until one is filed. If a buyer acquires the goods after arrival, the buyer may have to file the ISF to release the hold and is responsible for its accuracy, but the late-filing liability stays with whoever was the ISF Importer when the filing was due.
Do-not-load messages are the least common response. CBP states that DNL instructions are reserved for national security purposes; a missing or deficient ISF can contribute to one but is not the only factor, and when a DNL is tied to the ISF, CBP tells the carrier so.
The enforcement climate tightened in 2026. Executive Order 14411, Strengthening Customs Enforcement, signed June 3, 2026 (91 FR 35125), directs DHS to enforce liquidated damages claims against bonds and, within 90 days, to revise mitigation standards to set a minimum liquidated damages floor and eliminate mitigation for repeat offenders. CBP’s implementation page states that a minimum mitigation level is being set but, as of November 13, 2026, does not publish the amount. Until it does, importers should assume that mitigation of an ISF claim will be harder to obtain than the 2009 guidelines suggested, especially for repeat issues.
The ISF Bond and How to Amend or Withdraw a Filing
Every ISF must be backed by a bond under 19 CFR 149.5(b): a basic importation and entry bond with the 113.62 conditions, a custodial bond, an international carrier bond, an FTZ operator bond, or a dedicated ISF bond under Appendix D to Part 113. If the ISF Importer has no qualifying bond, the agent transmitting the filing may post its own. For a regular importer the practical answer is the continuous import bond already on file for entries, which carries the ISF condition in 113.62(j); the sizing and single-entry alternatives are covered in our comparison of single vs continuous customs bonds.
Agents need written authority. Under 149.5(c) an authorized agent must keep powers of attorney in English until revoked, and keep revoked powers of attorney and revocation letters for five years after revocation. The mechanics of granting that authority to a broker are in our guide to the customs power of attorney.
An ISF is a living filing until the vessel arrives. Section 149.2(d) requires the filer to update it if any information changes, or more accurate information becomes available, before the goods enter the limits of a US port. For cargo sold in transit, CBP’s FAQ calls for updating the original filing rather than deleting and refiling it, which would expose the importer to a late-filing claim; the new ISF Importer takes on accuracy under its own bond, while timeliness stays with the original party. Cargo rolled to a later vessel needs no amendment if the bill of lading does not change. CBP generally stops expecting updates once the vessel calls at the US port of arrival, and there is no need to edit the ISF afterwards to match the entry. If the goods will no longer be imported, 149.2(e) requires the filer to withdraw the ISF and state the reason; leaving an orphan ISF in place can itself draw a liquidated damages claim.
In practice the weak points are upstream. The seller, manufacturer and stuffing location sit with the supplier and the origin forwarder, and the ten elements have to agree with the commercial invoice and the later entry. A licensed broker running customs brokerage for the account can reconcile the ISF data against the entry before CBP does, which is where most inaccurate-ISF claims start. Ports with heavy transpacific volume, such as the gateways covered by our Los Angeles customs broker team, see the most rolled and split bookings, and therefore the most updates.
Frequently Asked Questions
What is an ISF filing?
An ISF filing is the Importer Security Filing required by 19 CFR Part 149 for cargo arriving in the United States by vessel. It gives CBP ten importer data elements, such as seller, buyer, manufacturer, country of origin and HTSUS number, before the cargo is loaded abroad, so CBP can screen the shipment in advance. Bulk cargo exempt from the 24-hour manifest rule is exempt from the ISF.
Who is responsible for the ISF filing?
The ISF Importer is responsible, defined in 19 CFR 149.1 as the party causing the goods to arrive by vessel: usually the owner, purchaser or consignee. A customs broker, forwarder or other agent can transmit the filing, but liability for late or inaccurate data stays with the ISF Importer. For foreign cargo remaining on board, the carrier or NVOCC is the ISF Importer.
When should we file an ISF?
File the first eight elements no later than 24 hours before the cargo is laden aboard the vessel at the foreign port. The container stuffing location and consolidator can follow, but no later than 24 hours before arrival at a US port. Filing as soon as the purchase order and booking are firm leaves time to correct errors before the loading deadline.
How do I file ISF with US customs?
The ISF is transmitted electronically to CBP, either through ABI using a filer code or through the ocean manifest system using a SCAC; there is no paper form. Most importers authorize a customs broker or forwarder under a power of attorney to file for them. A combined ISF and entry (Unified Entry) must be filed by the importer itself or a licensed customs broker.
What is the penalty for a late ISF?
CBP can assess liquidated damages of $5,000 per violation against the bond under 19 CFR 113.62(j). CBP’s guidance lists $5,000 for a late ISF, $5,000 for an inaccurate ISF and $5,000 for the first inaccurate update. Executive Order 14411 has directed CBP to set a minimum liquidated damages floor, which will narrow mitigation.
Does an ISF need its own bond?
Yes, every ISF must be covered by a bond, but a continuous import bond with the 19 CFR 113.62 conditions already qualifies. Other accepted bonds include custodial, international carrier and FTZ operator bonds, or a separate ISF bond. If the ISF Importer has none, the filing agent may post its own bond.
Do air shipments need an ISF?
No. The ISF requirement in 19 CFR 149.2 applies only to cargo arriving by vessel. Air, truck and rail shipments are covered by separate advance cargo information rules filed by the carrier, not by the Importer Security Filing.
