If you move ocean freight into the United States, you file ISFs. But a surprising number of small forwarders learned the mechanics on the job — what the form is, what CBP does with it, and what the penalties look like for a late or inaccurate filing aren’t always clearly documented in one place.
This guide covers ISF-10 from first principles: what CBP requires, what each field means, and how the deadline works.
What is an ISF?
ISF stands for Importer Security Filing. It’s a pre-arrival data submission required by U.S. Customs and Border Protection (CBP) under the Trade Act of 2002 and the SAFE Port Act of 2006. The requirement took effect in 2010.
The premise: CBP wants advance information about ocean shipments before the cargo arrives at a U.S. port, so it can assess security risk and target exams before the vessel docks. ISF is the mechanism.
There are two ISF forms: ISF-10 (for most ocean import shipments) and ISF-5 (for in-bond shipments, Freight Remaining on Board, and a few other scenarios). ISF-10 is the one most forwarders file daily.
The 10 fields
ISF-10 requires exactly 10 data elements. They fall into two groups based on when CBP needs them.
Must be filed no later than 24 hours before departure (or 24 hours before vessel arrival for short-voyage shipments):
- Seller — The entity selling the goods to the buyer. Usually the Chinese factory or trading company.
- Buyer — The entity buying the goods. Usually the U.S. importer of record.
- Importer of Record — The entity responsible for the merchandise once it enters the U.S. Same as buyer in most cases, but not always.
- Consignee — The party to whom the cargo is consigned in the U.S. Often the same as the importer.
- Manufacturer (or Supplier) — Who made the goods. Not always the same as the seller — a trading company often sells but doesn’t manufacture.
- Ship To Party — The first U.S. delivery destination after clearance.
- Country of Origin — Where the goods were manufactured, not where they were shipped from.
- Commodity HTS-6 — The Harmonized Tariff Schedule number at the 6-digit level.
Can be updated up to 24 hours before arrival (flexible fields):
- Vessel SCAC — The Standard Carrier Alpha Code for the ocean carrier.
- Container stuffing location — Departure port or location where the container was loaded.
There’s also an 11th required element — the consolidator — but it’s considered a flex field and can be updated until 24 hours before arrival.
The 24-hour deadline
The ISF must be on file with CBP 24 hours before the vessel departs the last foreign port. Not 24 hours before arrival. Departure.
For a vessel departing Shanghai on Tuesday at 6:00 AM, the ISF must be submitted by Monday at 6:00 AM Shanghai time — which is Sunday evening U.S. Eastern Time.
Short-voyage shipments (Canada and Mexico) have a different rule: 24 hours before arrival rather than departure. For trans-Pacific sailings, it’s always the departure-based rule.
Why this matters: If your booking confirmation hits your inbox Monday morning and you don’t see it until Tuesday, you’re already filing late. This is exactly the scenario TIO addresses — email intake is automatic, so the extraction and review cycle starts the moment the email arrives.
What happens when you miss the deadline?
CBP can assess a liquidated damages claim of up to $5,000 per violation for a late ISF. In practice, CBP uses a risk-tiered enforcement model — first-time violations on low-risk shipments are often handled with a warning. Repeat violations or high-risk cargo attract larger penalties.
Beyond penalties, a late ISF can result in a CBP-issued Do Not Load order or a mandatory exam on arrival. Exams are expensive (container unstuffing at a CBP-approved facility runs $1,500–$5,000+ depending on port) and they delay your customer’s freight.
The accuracy requirement
CBP also penalizes inaccurate ISFs. The HTS code, country of origin, and manufacturer fields are the most common sources of error — especially when information comes from a foreign factory that doesn’t always get the commodity description right.
TIO applies a confidence score to each extracted field and flags low-confidence fields for team review before the lot is submitted. The filer reviews every extraction before anything goes to the TMS. That review step is not optional — it’s enforced in the workflow.
Who is the filer of record?
The ISF filer of record is the party whose ISF filer code is on the submission. For most small U.S.-based forwarders who don’t hold a customs broker license, this is the licensed third-party broker they outsource to. That broker carries the regulatory liability.
If you’re using TIO, the filer-in-loop rule applies regardless: the human filer reviews and approves every ISF before it leaves TIO. No autonomous filing. The filer of record question is a compliance and contractual matter between you and your broker — TIO handles the data flow, not the licensing.
Summary
ISF-10 is a 10-field CBP pre-arrival filing required for ocean imports. The 24-hour deadline runs from vessel departure, not arrival. Late or inaccurate filings carry up to $5,000 per violation in liquidated damages. Small forwarders running 50–100 jobs per month have significant deadline exposure — and most are managing it with email and manual TMS data entry.
TIO addresses this by connecting directly to your inbox, extracting job fields automatically, and queuing them for team review before they reach your TMS. The compliance step is streamlined, not bypassed — the filer stays in the loop on every job.
For the full field-by-field reference, see ISF-10 field definitions in the TIO docs.