If you’re importing goods into the United States by ocean freight, there’s one term you need to get very familiar with—ISF Importer Security Filing. Often overlooked by first-timers, ISF plays a critical role in getting your cargo cleared through U.S. Customs smoothly.

Think of ISF as your shipment’s passport. If it’s incomplete or filed late, you could face penalties, shipment delays, or even cargo holds. This guide is written in plain English for first-time importers or growing eCommerce brands using services like FBA prep or product fulfillment solutions in the U.S.

What Is ISF Importer Security Filing?

ISF, or Importer Security Filing, is a U.S. Customs and Border Protection (CBP) requirement for ocean shipments. It must be filed at least 24 hours before your cargo is loaded onto a vessel bound for the U.S. This filing provides CBP with important security-related data about your shipment.

📦 Applies To: All ocean freight entering the U.S.—not air or ground shipments.

🚫 Penalty for Late Filing: Up to $5,000 per violation.

Why ISF Matters: It’s About Security and Speed

CBP uses ISF data to assess risk and prevent threats before cargo reaches U.S. shores. But from a business standpoint, filing ISF correctly also:

Who Is Responsible for Filing ISF?

The Importer of Record (IOR) is responsible for submitting the ISF. That’s often the U.S.-based importer (you), or your licensed customs broker or freight forwarder (especially if you’re working with Amazon FBA freight forwarder specialists).

Pro tip: Even if someone else files ISF on your behalf, you are still held legally responsible for accuracy and timeliness.

ISF Filing Checklist: What You Need

Here’s what must be included in your ISF submission:

  1. Seller (name and address)
  2. Buyer (name and address)