Gather the 10 data elements required from the importer: seller, buyer, importer of record number, consignee number, manufacturer, ship-to party, country of origin, commodity HTSUS, container stuffing location, and consolidator.
Submit the ISF to CBP via an ACE-certified filing agent or your own ACE portal account **no later than 24 hours before cargo is laden (loaded) aboard the vessel** at the foreign port of export.
File the 2 carrier data elements (vessel stow plan and container status messages) separately through the ocean carrier or their agent.
After filing, monitor CBP's `ISF_ACCEPTED` and `ISF_MATCHED` messages in ACE; resolve any mismatch or rejection notices before the vessel arrives.
Update the ISF if any data elements change after submission — updates are required as soon as discrepancies are known and no later than 24 hours before US arrival.
Known gotchas
The ISF deadline is **24 hours before cargo is laden aboard the vessel** at the foreign port — not 24 hours before vessel departure or arrival; by vessel departure the window has already closed.
Late, inaccurate, or incomplete filings each carry a liquidated damages penalty of up to **$5,000 per violation** from CBP.
The ISF is not required for cargo traveling by air, rail, or truck — it applies only to ocean shipments arriving in the United States.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp