How to Submit ISF to U.S. Customs Correctly

To correctly submit an Importer Security Filing (ISF), a registered U.S. importer first needs to gather 10 required data elements before transmitting the ISF to U.S. Customs and Border Protection (CBP), usually through the Automated Commercial Environment (ACE) Portal on CBP’s website. 

How Do You Submit ISF to U.S. Customs?

Submitting an ISF to U.S. Customs can be broken down into two major steps:

• Getting the 10 data points CBP requires from importers on the ISF form
• Filling out and transmitting the form to CBP, usually via electronic means such as the ACE portal 

The ISF is sometimes referred to as the 10+2 filing since the importer needs to fill out 10 elements on the document while the carrier is responsible for two.

What Information Does an Importer Need to File an ISF?

The full list of information required by the ISF importer is as follows:

• Buyer
• Seller
• Consignee number(s)
• Importer of record number/FTZ applicant identification number
• Ship to party 
• Country of origin 
• Manufacturer (or supplier)
• Commodity Harmonized Tariff Schedule 
• Consolidator
• Container stuffing location

These data elements must be submitted for shipments of goods intended for use or resale in the U.S. A separate ISF-5 document is used for transit cargo that is only being imported temporarily.

Where Do You File an ISF: ACE, ABI, or a Customs Broker?

Importers can file their ISF documents via the ACE portal, which can be accessed on CBP’s website. This portal is where U.S. importers submit most of their customs documents, such as CBP Form 7501, for the agency to review.

Business owners often partner with a Licensed Customs Broker to simplify complex customs business, and a broker can submit the ISF on an importer’s behalf using Automated Broker Interface (ABI) software, a high-speed transmission method usually only available to customs brokerages.

When Must ISF Be Submitted?

CBP requires importers to submit the ISF for an ocean shipment 24 hours or more before the goods are loaded onto their shipping vessel. The ISF document is required for all formal shipments imported via ocean freight, with the exception of bulk goods.

What Happens After You Submit an ISF?

After CBP receives and reviews an ISF, they assign it one of three statuses:

• Accepted: CBP accepts the ISF with no adjustments necessary
• Accepted With Warning(s): While accepted, CBP identifies minor issues in need of review and possible correction
• Rejected: CBP does not accept the ISF due to substantial documentation errors or late filing

The reasons CBP can decide to reject an ISF include significant data mismatches between related documents, severe formatting errors, and missing or invalid customs bond information. 

What Happens if an ISF Is Late, Inaccurate, or Rejected?

CBP may assess fines of up to $5,000 in liquidated damages for each late or inaccurate ISF they receive. Non-monetary penalties range from delays and cargo inspections to stricter enforcement actions on future imported shipments. 

Businesses certified with the Customs Trade Partnership Against Terrorism (CTPAT) may see their privileges and membership revoked as well. 

Importers can avoid these consequences by amending any documentation errors on a rejected ISF before the cargo arrives at its first U.S. port, ideally as soon as the new information is available. 

Can You Amend an ISF After Submission?

Yes, importers can amend ISFs flagged as “accepted with warnings” while cargo is in transit within a specific time frame, usually no less than 24 hours before the cargo vessel reaches its first U.S. port. 

A rejected ISF cannot be amended, but importers can submit a new ISF to CBP if their initial submission is rejected.

How to Avoid Common ISF Filing Mistakes

Importers need to avoid ISF errors associated with accuracy and timing when it comes to filing this customs document. Specifically, importers should follow these guidelines to keep their ISFs timely and compliant:

• Don’t file late: submit the ISF 24 hours or more before vessel lading
• Double check the bill of lading (BoL) number on the document for accuracy
• Quickly make any necessary updates to the ISF while the shipment is in transit
• Finalize any ISFs submitted with flexible filing codes 
• Ensure supplier and manufacturer data is accurate
• Withdraw ISFs for goods that don’t end up getting imported
• Respond to all “accepted with warning” messages promptly

Making sure the ISF is filed accurately and on time is one of the core expectations of any IOR in the United States when they bring a shipment into the country from a foreign supplier. Since the penalties for non-compliance can be so expensive, importers often choose to partner with an experienced customs broker when submitting this and other documents CBP requires. 

Should You File ISF Yourself or Use a Licensed Customs Broker?

A confident and knowledgeable importer can file their own ISF if they’re certain they can provide accurate information and meet CBP’s standard of reasonable care. Importers who are uncertain about CBP documentation regulations can work with a Licensed Customs Broker whose day-to-day experience with government paperwork is leveraged to ensure that the ISF is filed correctly. 

If you have questions about filing an ISF, call us at (855) 912-0406 or fill out a contact form online today.

Sources

Reasonable Care: An Informed Compliance Publication, U.S. Customs and Border Protection, September 2017

Import Security Filing (ISF) - When to submit to CBP, U.S. Customs and Border Protection, 11/4/2025

ACE, U.S. Customs and Border Protection

Importer Security Filing and Additional Carrier Requirements, U.S. Customs and Border Protection, August 2009