What is 24-Hour Rule?

The 24-Hour Rule is a U.S. Customs requirement that ocean carriers transmit cargo manifest data to CBP at least 24 hours before containers are loaded onto a vessel at a foreign port destined for the United States. The rule gives CBP time to screen inbound cargo for security risks before it leaves origin, and it works alongside the Importer Security Filing (ISF, or “10+2”) to give the agency a complete picture of what is heading to U.S. ports.