Importer Security Filing (ISF): Full Guide + 5 Steps to File

If there’s one thing I’ve learned in this industry, it’s that paperwork is king. And when it comes to U.S.-bound cargo, Importer Security Filing is one of those regulatory hoops you just have to jump through.

Even if you’re not directly responsible for filing, knowing the ins and outs of ISF can save you and your clients from expensive delays and headaches. I’ve seen plenty of vessel agents get caught off guard by ISF requirements—missing deadlines, scrambling for the right data, or assuming someone else had it covered.

Trust me, CBP (U.S. Customs and Border Protection) doesn’t care about excuses. If an ISF is late, missing, or incorrect, they’ll slap your client with penalties that make their eyes water. Let’s break it down—what an ISF is, who files it, when it’s due, and why it’s something you need to stay ahead of.

What is an ISF?

Importer Security Filing, also called “10+2”, is a requirement enforced by CBP. It applies to ocean shipments arriving in the U.S. and is meant to improve cargo security by providing CBP with advance information.

An ISF contains the following details:

• Importer of Record number
• Consignee number
• Seller name and address
• Buyer name and address
• Manufacturer (or supplier) name and address
• Ship-to party name and address
• Container stuffing location
• Consolidator name and address
• Bill of Lading number
• Commodity HTSUS code (Harmonized Tariff Schedule of the United States)

CBP also requires vessel stow plans and container status messages from carriers—hence the “10+2” name.

ISF 5 vs. ISF 10+2 – What’s the Difference?

Most of the time, when people talk about ISF, they mean ISF 10+2, which applies to imported commercial cargo arriving in the U.S. However, there’s also ISF 5, which is for goods that aren’t being formally entered into U.S. commerce—things like transit cargo, Foreign Trade Zone shipments, or freight remaining on board (FROB).

An ISF 5 only requires:

• Booking party name/address
• Foreign port of unlading
• Place of delivery
• Ship-to party
• Bill of Lading number

If you’re handling vessel schedules, you’ll want to know which type of ISF applies to a shipment so you’re not caught off guard when CBP comes knocking.

For a deeper understanding of how cargo information flows in shipping, check out our cargo manifests explained blog.

Who is Responsible for Filing and Paying the ISF?

The importer of record is legally responsible for filing the ISF, but here’s the reality: if something goes wrong, everyone involved in the shipment is going to feel the pain.

A lot of times, the importer relies on their freight forwarder, customs broker, or vessel agent to file on their behalf. And that’s where things can get messy.

I’ve seen vessel agents get pulled into ISF disputes because the importer assumed they were handling it. Other times, forwarders drop the ball, and the vessel agent is the one left scrambling to figure out why a shipment is being held.

If you’re working with foreign suppliers, make sure they understand that ISF isn’t optional. If they’re not familiar with the process, recommend a licensed customs broker who knows what they’re doing.

How Much is the ISF Fee?

CBP doesn’t charge a filing fee, but that doesn’t mean it’s free. Most customs brokers and freight forwarders charge anywhere from $30 to $50 per ISF filing—sometimes more if they’re handling multiple corrections.

The real cost comes from late filings or errors. ISF penalties can go up to significant amounts, and CBP isn’t shy about enforcing them. We’ll touch on this a little later on.

When Must an ISF Be Filed?

An ISF must be submitted at least 24 hours before cargo is loaded onto the vessel. That means before it even leaves the foreign port.

If you miss the deadline, CBP will still accept the filing, but they may:

• Issue a fine
• Place the shipment on customs hold, delaying clearance
• Withhold permission to unload the container in the U.S.

Learn more about other requirements surrounding import and clearances with our blog on VECS (Vessel Entrance & Clearance System.)

How Do You File an ISF?

Whether you’re handling the process directly or guiding your clients through it, understanding how to file an ISF properly can save time, money, and stress. Here’s how it’s done:

1. Gather Required Information

Before you even think about submitting an ISF, make sure you have all 10 required data points (plus the carrier’s “2” elements if applicable). Missing even one of these can result in a rejected filing or a compliance violation.

The challenge? Getting this information from multiple parties—importers, shippers, freight forwarders, and consolidators—before the vessel even leaves the foreign port. The best approach is to establish a clear process with your clients and their supply chain partners ahead of time so everyone knows what’s needed.

One critical document that often gets overlooked in ISF compliance is the Commercial Invoice and Packing List. This document helps ensure accuracy in shipment details, proper classification under the Harmonized Tariff Schedule, and alignment with ISF data submitted to CBP. If you want a deep dive into why CIPL is essential and how vessel agents should handle it, read CIPL (Commercial Invoice and Packing List).

2. Choose a Filing Method

Once you’ve gathered all the necessary details, you need to decide how you’re going to file the ISF. There are three main options:

• Use a Customs Broker – Most importers work with a licensed customs broker who files ISF on their behalf. This is the easiest option if you’re not familiar with CBP’s systems.
• Self-File Using ISF Software – Some companies prefer to handle ISF filings in-house using self-filing software that integrates with CBP. This requires training but gives the importer more control.
• File Directly via the Automated Broker Interface (ABI) – Importers and brokers who are registered with CBP’s ACE system can file ISFs through the Automated Broker Interface (ABI).

If your client prefers to self-file, they should read ACE Manifests for Vessel Agents: A Guide to CBP Compliance for details on setting up an ACE Manifest account.

3. Submit Through CBP’s ACE Portal: Upload ISF Information into AMS and File via ACE

Once you’ve chosen a filing method, the ISF process involves two critical steps:

1. Uploading the ISF data into AMS (Automated Manifest System)
   • The AMS is CBP’s electronic system used by carriers, NVOCCs, and freight forwarders to transmit manifest data before the vessel arrives in the U.S.
   • The ISF details must be properly associated with the manifest data submitted in AMS to ensure a smooth clearance process.
   • If the manifest data and ISF don’t match, CBP may flag the shipment for additional screening or issue penalties.
2. Submitting the ISF through CBP’s ACE Portal (Automated Commercial Environment)
   • The ACE system is where importers, brokers, and self-filers submit ISF data to CBP.
   • Once the ISF is filed in ACE, CBP cross-checks it with the manifest details from AMS.
   • If everything aligns, the shipment is cleared for processing. If there’s a discrepancy, CBP can issue penalties or even hold the cargo.

Once again, make sure the ISF is submitted at least 24 hours before the cargo is loaded onto the vessel.

4. Confirm Bill of Lading (BOL) Linkage

This is one of the most common issues people have. The ISF must be linked to the correct Bill of Lading (BOL). If the BOL number in the ISF doesn’t match the one submitted by the carrier, CBP won’t be able to process the filing correctly.

In situations like this, having a well-documented Statement of Facts (SOF) can help protect vessel agents and their clients from disputes over delays, cargo handling, and compliance issues. If you want to learn how SOFs can safeguard your operations, check out Statements of Fact in shipping blog.

5. Monitor and Update If Necessary

Even after the ISF is filed, your job isn’t done. Any changes to the shipment must be updated in the ISF before vessel arrival.

CBP allows certain ISF elements to be corrected or amended, but only if updates are submitted in time. Failing to update an ISF when needed can result in the same penalties as failing to file at all.

Common scenarios where an ISF update is required:

• The shipment details change (e.g., new consignee, updated ship-to address).
• The BOL number was entered incorrectly.
• The Harmonized Tariff Schedule (HTS) code was wrong and needs correction.
• A different consolidator or stuffing location was used.

Keep detailed records of all ISF filings, updates, and confirmations. Using a tool like Base can help track ISF deadlines, documents, and changes so nothing falls through the cracks.

Fines for a Late ISF

There’s a saying: “A day late is a dollar short.” But when it comes to ISF compliance, a day late could mean thousands of dollars short—not to mention a frustrated client and a serious disruption in supply chain operations.

CBP isn’t lenient when it comes to ISF deadlines. If the filing is late, incorrect, or missing altogether, the importer can be fined up to $5,000 per violation. That might not sound like much in the grand scheme of international shipping, but when you start adding up multiple shipments—or repeated violations—it turns into a financial black hole.

Some of the most common ISF mistakes that lead to penalties include:

• Incorrect HTS (Harmonized Tariff Schedule) codes – Even a small mistake in classification can lead to non-compliance.
• Mismatched Bill of Lading (BOL) numbers – If the ISF doesn’t match what the carrier has on file, it can trigger a problem.
• Wrong consignee or ship-to-party details – CBP needs to know exactly where the cargo is going.
• Incomplete or missing container stuffing location – If this information is left out or incorrect, it could delay clearance.
• Failure to amend an ISF when shipment details change – If something changes post-filing and you don’t update CBP, expect a fine.

But the real pain comes when Customs decides to hold a shipment. I’ve seen clients assume that if they just pay the fine, everything will move along smoothly—not so fast. A held shipment means logistics chaos, and the costs start piling up quickly:

• Demurrage fees – If the shipment sits too long at the terminal, you’ll pay daily storage fees that can add up fast.
• Detention fees – If the container is stuck longer than the free time allowed, the carrier will charge per day.
• Port storage fees – If the goods can’t move, the port authority will start racking up charges.
• Missed delivery deadlines – If the cargo doesn’t make it to its destination on time, contracts can be affected.

This is where things spiral out of control. Let’s say a container gets held for five days due to an ISF mistake. That means:

• $5,000 ISF penalty
• $150 per day in demurrage fees ($750 total)
• $200 per day in detention charges ($1,000 total)
• Additional storage fees from the port

By the time everything is resolved, a single mistake could cost more than $10,000—just because an ISF wasn’t filed correctly or on time.

Conclusion on Importer Security Filing

As you can see, ISF compliance is essential. Vessel agents are often caught in the middle when an ISF isn’t filed properly. Maybe the importer assumed the forwarder had it handled, or maybe a supplier overseas gave incorrect details. Either way, when the shipment gets held, you’re the one getting the angry phone calls.

That’s why having a system to manage ISF-related documentation and deadlines is critical. Base helps vessel agents and port operators stay organized by:

• Tracking shipment-related documents (like Bills of Lading and commercial invoices).
• Providing a centralized system to store key compliance documents.
• Managing communications between vessel agents, importers, and other stakeholders.

Don’t let an ISF mistake cost your clients time and money. Use Base to stay compliant, reduce errors, and protect your bottom line.

Key Takeaways

• ISF is mandatory for all ocean shipments entering the U.S. It must be filed at least 24 hours before vessel loading to avoid penalties.
• Filing errors can cost up to $5,000 per violation. Mistakes like incorrect HTS codes, mismatched BOL numbers, or missing consignee details can trigger fines and shipment holds.
• Late or inaccurate ISFs can lead to costly delays. Demurrage, detention, and port storage fees can quickly add up to $10,000+ per shipment if a container is held.
• Base can help you stay organized and prevents compliance issues.

Frequently Asked Questions