What Is ISF Filing?
The Importer Security Filing — universally called ISF or "10+2" — is an electronic pre-arrival data submission that US Customs and Border Protection (CBP) requires for every commercial ocean shipment heading to the United States. Ten data elements come from the importer; two come from the ocean carrier. CBP uses the data to screen cargo for risk before the vessel leaves the origin port — not after it docks in the US.
ISF was introduced under the SAFE Port Act of 2006 and has been mandatory since January 2009. Unlike the formal customs entry filed when cargo arrives, ISF must be transmitted to CBP before the vessel departs from its last foreign port. The earlier CBP receives accurate data, the better it can target high-risk shipments and wave through low-risk cargo without additional scrutiny.
ISF applies strictly to ocean freight. Air cargo uses a different advance data regime (Advance Air Manifest). If your goods are traveling by sea to any US port, ISF is mandatory regardless of commodity, value, or container size.
Who Is Responsible?
The legal obligation to file ISF sits with the importer of record — the company or individual named on the customs entry as responsible for the shipment. In practice, nearly all importers delegate this to a licensed customs broker, since brokers maintain direct electronic connections to CBP's Automated Broker Interface (ABI). The delegation, however, does not transfer legal liability: if the broker files late because you sent documents late, CBP holds the importer of record accountable.
Your purchase terms also shape your compliance risk. Under incoterms such as EXW or FCA, you control origin-side logistics and must collect all supplier documents — commercial invoice, packing list, manufacturer details — in time for your broker to meet the pre-departure deadline. If you buy DDP or DAP, where the seller controls more of the transport leg, confirm in writing who is responsible for coordinating ISF before any cargo moves.
The 10 Importer Data Elements
The importer — almost always through a licensed customs broker — must provide these ten fields when submitting an ISF:
| # | Element | What CBP needs |
|---|---|---|
| 1 | Seller | Name and address of the party selling the goods |
| 2 | Buyer | Name and address of the purchasing party |
| 3 | Importer of record number | US EIN, SSN, or CBP-assigned importer number |
| 4 | Consignee number | US party to whom the goods are legally consigned |
| 5 | Manufacturer (or supplier) | Factory or origin-supplier name and address |
| 6 | Ship-to party | Final US delivery address |
| 7 | Country of origin | Where goods were manufactured or substantially transformed |
| 8 | HTS-6 commodity code | Six-digit Harmonized Tariff Schedule number |
| 9 | Container stuffing location | Name and address where the container was packed |
| 10 | Consolidator (stuffer) | Entity that physically loaded the container |
Elements 1–8 must be filed at least 24 hours before vessel departure. Elements 9 and 10 — stuffing location and consolidator — may be updated up to 24 hours before the vessel's arrival at the first US port if those details were not available at the time of initial filing. CBP refers to this partial submission as an "ISF Pending."
Two elements cause problems more consistently than the rest. HTS-6 codes are updated periodically; a code used on last year's entry may no longer be correct, and an inaccurate code can flag the shipment for further review. Country of origin is not always the country of purchase — goods manufactured across multiple countries follow the "substantial transformation" test, which can produce a different origin answer than the invoice address suggests.
The 2 Carrier Elements
The ocean carrier — not the importer — is responsible for the "2" in 10+2:
- Vessel stow plan: The physical location of every container aboard the ship. The carrier files this within 48 hours of departing the last foreign port, or before departure if the voyage is shorter than 48 hours.
- Container status messages (CSMs): Event-driven updates tracking container movements — gate-in, load, discharge, gate-out. These allow CBP to maintain a running location trace for each container.
As an importer you have no direct filing obligation for these two elements. That said, carrier non-compliance feeds into CBP's risk scoring for the vessel as a whole, which can increase the probability that your cargo is selected for examination — even when your own ISF was filed accurately and on time.
The 24-Hour Departure Deadline
ISF must be submitted at least 24 hours before the vessel departs its last foreign port of lading — not 24 hours before arrival at the US port of discharge. For a container departing Shanghai, the clock starts 24 hours before the ship leaves China, not when it approaches Los Angeles.
On most long-haul lanes this window is workable: Asia-to-US West Coast transits typically run 14–18 days, and Asia-to-US East Coast via Panama runs 24–30 days. Importers have adequate time to file as long as their supplier delivers shipping documents in advance of the sailing date.
The deadline becomes genuinely tight in two scenarios. First, short-transit origins: ocean shipments from Mexico, the Caribbean, or Canada by feeder vessel can have transits as short as 2–5 days, leaving almost no buffer if the supplier invoice arrives late. Second, last-minute bookings: when a cargo booking is confirmed close to vessel departure, it can be difficult to assemble all ten ISF elements before the 24-hour clock expires.
The safest approach is to file early and amend. Submit ISF as soon as you have a booking confirmation and initial supplier documents, flagging elements 9 and 10 as pending if the consolidator is not yet confirmed. An on-time submission with a pending amendment is consistently safer than waiting for a complete data set and filing at the last minute.
Consequences of Late or Inaccurate Filing
A late, missing, or materially inaccurate ISF can result in liquidated damages up to $5,000 per violation under CBP's published enforcement schedule. The direct financial penalty is often not the most disruptive consequence. CBP has three additional enforcement tools that compound the cost quickly:
- Do Not Load (DNL) order: CBP instructs the carrier not to load your container until the ISF issue is resolved. Your cargo sits at the origin terminal or warehouse while the vessel sails without it.
- Intensive cargo examination: On arrival, CBP orders a physical inspection or non-intrusive imaging scan of the container. Exam fees are passed to the importer, and the process can delay release by several days — during which demurrage and terminal storage charges accumulate.
- Cargo hold: A formal hold prevents the freight from being released to you even after unloading. Every day under hold generates port storage fees from the terminal operator.
Importers who file consistently and accurately over time build a lower-risk profile in CBP's Automated Targeting System. That history reduces the likelihood of discretionary examination on future shipments, making compliance genuinely self-reinforcing.
ISF for LCL and Consolidated Shipments
ISF applies to every US ocean import — not just full container loads. Whether your cargo fills a full container or moves as a single pallet in an LCL consolidation, you are individually required to file ISF covering your portion of the shipment.
For LCL moves, each importer whose goods are co-loaded into a shared container files their own ISF independently. The non-vessel operating common carrier (NVOCC) or freight forwarder managing the consolidation should alert you to file ISF when the booking is confirmed. A costly and common assumption is that the NVOCC handles ISF filing on your behalf — unless you have a written agreement specifying this and the NVOCC holds an ISF filer bond for your cargo, the obligation remains yours.
If you are new to LCL shipping, settle ISF responsibilities in writing with your logistics partner before cargo is tendered at the origin warehouse.
Who Files ISF in Practice?
For the vast majority of importers, ISF is filed by a licensed customs broker using an ABI software connection to CBP. The broker formats your shipping documents into CBP's ISF data specification and transmits the filing electronically. CBP issues a transaction number confirming receipt — that number is your proof of timely filing, and you should request it for every shipment your broker files.
The standard workflow:
- You receive a booking confirmation from your freight forwarder.
- Your supplier sends the commercial invoice, packing list, and shipper details.
- Your broker files ISF via ABI, flagging stuffing location and consolidator as pending if not yet confirmed.
- CBP issues an ISF transaction number.
- The broker updates elements 9 and 10 once confirmed, within the allowed amendment window before vessel arrival.
- On arrival, your broker files the formal customs entry — but ISF must already be on file and consistent with entry data.
CBP cross-references ISF data against the formal customs entry. Discrepancies in HTS codes, country of origin, or manufacturer details are flagged and can attract additional scrutiny. Ensure your broker is using data from the same source documents for both filings.
