What is ISF (Importer Security Filing / 10+2)?

If you ship ocean freight into the United States, you need to file an Importer Security Filing (ISF) before your cargo is loaded onto the vessel. This is not optional. U.S. Customs and Border Protection (CBP) requires this security filing for every ocean shipment entering U.S. ports. Non-compliance can result in fines of up to $10,000 per violation. This guide covers what the ISF is, who files it, which data elements are required, and what happens when importers get it wrong.

What Is ISF (Importer Security Filing)?

An Importer Security Filing is a set of data that must be transmitted electronically to CBP before ocean cargo arrives in the United States. Its purpose is to give border protection agencies advance visibility into what is entering the country so they can identify high-risk shipments and prevent smuggling.

The new rule went into effect on January 26, 2009. CBP used a flexible enforcement period during the first year. Full ISF compliance became mandatory on January 26, 2010. All ISF filings must be submitted electronically through the Automated Broker Interface (ABI) or the Automated Commercial Environment (ACE) portal, so importers or filers must establish the required electronic filing connection or process to submit successfully. There is no paper-based option.

For a deeper look at the process and its benefits, see KlearNow’s ISF overview.

What Is the 10+2 Rule?

What Does “10+2” Mean?

The ISF is commonly known as the “10+2” rule. The name refers to the structure of the filing. The importer must submit 10 data elements to CBP. The ocean carrier must separately provide 2 additional data elements. Together, these 12 pieces of information make up the complete importer security filing.

The 10 Importer Data Elements

The ISF importer must provide these 10 data elements:

#	Data Element	What It Covers
1	Seller	Last known entity selling the goods. Found on the commercial invoice.
2	Buyer	Entity purchasing the goods. Found on the commercial invoice.
3	Importer of record number	IRS number, EIN, or social security number of the entity liable for duties and responsible for meeting all statutory and regulatory requirements incurred from importation.
4	Consignee number	IRS number or customs-assigned number of the party in the U.S. on whose account goods are shipped.
5	Manufacturer or supplier	The party supplying the finished goods from the country of origin.
6	Ship to party	First deliver to party scheduled to physically receive the goods after release from customs custody.
7	Country of origin	Country of manufacture, production, or growth per U.S. import laws.
8	Commodity HTSUS number	Harmonized Tariff Schedule classification at a minimum of 6 digits.
9	Container stuffing location	Physical location where goods were stuffed into the container.
10	Consolidator (stuffer)	Party who stuffed or arranged stuffing of the container.

The manufacturer, country of origin, and commodity HTSUS number must contain accurate information and remain linked to one another at the line item level within the filing.

The 2 Carrier Data Elements

The steamship line submits two additional carrier requirements:

1. Vessel stow plan submitted to CBP.
2. Container status messages tracking the container through its journey.

These are entirely the responsibility of the carrier, not the importer.

Why CBP Requires This Information

CBP uses ISF data to target high-risk shipments before they reach U.S. ports. The filing gives CBP information to evaluate cargo and transportation risk before arrival and pushes supply chain security back to the container stuffing location at the foreign port. Improved targeting means fewer inspections for low-risk cargo. ISF data is used for security purposes only and is exempt from Freedom of Information Act disclosure.

When Must ISF Be Filed?

The 24-Hour Rule

Eight of the 10 data elements must be filed no later than 24 hours before cargo is laden aboard the vessel at the foreign port. These include the seller, buyer, importer of record number, consignee number, manufacturer, ship to party, country of origin, and HTSUS number.

The container stuffing location and consolidator can be filed later, but must be submitted no later than 24 hours before arrival at the U.S. port of discharge.

Filing for Break Bulk Cargo

ISF for break bulk cargo must be filed no later than 24 hours prior to arrival at the port of discharge, and importers still must comply with ISF timing requirements even though the filing details differ from containerized shipments. For break bulk shipments, the container stuffing location is replaced by the physical location where the goods were made ship ready. The consolidator field captures the party who arranged for the goods to be made ship ready.

Updating ISF Information

If any data changes after the initial filing, the ISF must be amended before the shipment enters the limits of the port of discharge. Only the original filer can update or cancel the filing. If goods are no longer intended for import into the U.S., the ISF can be deleted.

Common Timing Mistakes

The most frequent errors include filing after the 24-hour deadline, submitting incorrect bill of lading numbers, and failing to amend when shipment details change. Late or inaccurate ISF filings commonly violate CBP rules and are the top triggers for enforcement action.

Who Is Responsible for Filing ISF?

The Importer of Record holds ultimate responsibility for the timely, accurate, and complete submission of all 10 data elements. This is the entity liable for payment of all duties and for meeting all regulations tied to the importation.

In practice, most importers delegate the actual filing to a licensed customs broker or freight forwarder. However, delegating the task does not transfer liability. If the filing is late or inaccurate, liquidated damages are assessed against the bond holder who posted for the ISF.

For ISF filings, the bill of lading number ties the security filing to the manifest data and to the entry for entry purposes. It must be reported at the lowest bill of lading level, whether that is a house bill or a regular bill.

For FROB (foreign cargo remaining on board), I.E., and T&E shipments, only 5 data elements are required. This streamlined filing is known as the ISF-5. The five elements are: booking party, foreign port of unlading (using the Schedule K port code), place of delivery, ship to party, and commodity HTSUS number.

What Types of Cargo Require ISF?

ISF must be filed for ocean cargo only when these cargo categories are imported into the U.S. for entry purposes. The three categories that require a filing are:

• Containerized cargo: Both FCL (full container load) and LCL (less than container load) shipments require ISF, including when planning or reserving cargo space for the shipment. This covers the vast majority of ocean freight entering the U.S.
• Break bulk shipments: Goods loaded individually rather than inside standard containers also need an ISF filing.
• Ro-Ro shipments: Roll-on/roll-off cargo such as vehicles requires ISF.

Bulk cargo is exempt. Commodities like grain, coal, and oil that fill entire cargo holds without packaging or containerization do not require an ISF filing.

Goods arriving by vessel into Canada or Mexico and then trucked or railed into the U.S. are also exempt from ISF requirements.

What Happens if ISF Is Filed Late or Incorrectly?

Penalties and Liquidated Damages

CBP enforces ISF through the assessment of liquidated damages. Fines can reach up to $10,000 per violation for failure to submit the ISF timely, accurately, or completely. First-time violations can often be mitigated to $1,000 to $2,000 through a well-prepared petition, but repeat violations face steeper penalties.

Cargo Holds and Delays

Non-compliant ISF filings can result in cargo holds at U.S. ports. CBP may refuse to unload cargo until it receives the required information and has reviewed the documentation. This creates supply chain delays that compound into storage charges, demurrage fees, and missed delivery windows.

End of Three-Strike Leniency

CBP no longer requires a three-strike leniency approach for ISF violations. Since June 30, 2016, ports can issue liquidated damages on the first violation without sending claims to CBP headquarters for approval. The enforcement environment has tightened considerably. C-TPAT members may receive additional mitigation, but compliance is expected from every importer.

An importer’s existing continuous bond covers the ISF filing. Importers without a continuous bond must post a single entry bond for each ISF filing.

How Technology Helps Manage ISF Compliance

Managing ISF filings manually introduces risk at every step. Data must be gathered from multiple parties across different time zones. Deadlines are tight. A single incorrect HTSUS number or missing lading number can trigger penalties.

AI-powered platforms like KlearNow.AI automate the heavy lifting. The platform digitizes trade documents, extracts required data elements, validates classifications before transmission to CBP, and tracks filing deadlines. Automated data ingestion reduces the manual entry errors that cause the majority of ISF violations.

Frequently Asked Questions (FAQs)

What is ISF? 

ISF stands for Importer Security Filing. It is a mandatory electronic filing submitted to U.S. Customs and Border Protection for all ocean cargo entering the United States.

What is the 10+2 rule? 

The 10+2 rule requires the ISF importer to submit 10 data elements and the ocean carrier to provide 2 additional data elements (vessel stow plan and container status messages) for every ocean freight shipment.

When must ISF be filed? 

ISF must be filed no later than 24 hours before cargo is laden aboard the vessel at the foreign port of departure.

Who is responsible for filing ISF? 

The Importer of Record is ultimately responsible. The filing can be delegated to a customs broker or freight forwarder, but the importer remains liable for compliance.

What happens if an ISF is filed late? 

CBP can assess liquidated damages of up to $10,000 per violation and place cargo holds at the port until the filing is corrected.

Can ISF information be updated after filing? 

Yes. If shipment details change, the ISF must be amended before the vessel enters the limits of the U.S. port of discharge. Only the original filer can make updates.

Does every ocean shipment require ISF? 

Most do. Containerized cargo, break bulk shipments, and Ro-Ro shipments all require ISF. Bulk cargo (grain, coal, oil) is exempt from the filing requirement.

What documents are required for U.S. customs clearance? 

Key documents include the ISF, commercial invoice, bill of lading, packing list, entry summary, customs bond, and certificate of origin. Additional documents may be required depending on the commodity.

What does FOB mean in ocean freight? 

FOB stands for Free on Board. It means the seller delivers the goods onto the vessel at the named port of shipment. Risk and cost transfer to the buyer once the goods are loaded.

What are the three types of freight documentation? 

The three categories are commercial documents (commercial invoice, packing list), transport documents (bill of lading, airway bill), and regulatory documents (ISF, entry summary, certificates of origin, customs bonds).