This transaction set communicates cargo manifest and consist details to U.S. Customs and Border Protection in advance of shipment arrival. Freight forwarders, customs brokers, and ocean carriers send the 358 to report vessel, container, and bill of lading information for inbound maritime shipments. The transmission typically occurs in response to a shipment being scheduled for U.S. entry or as part of pre-clearance filing requirements. The M10 (Manifest Identifying Information) segment establishes the manifest reference and timing, the P4 (U.S. Port Information) segment specifies the port of entry and related details, and the MBL (Bill of Lading) segment lists individual shipments with their commercial identifiers.

Consider a scenario where Ocean Express Shipping prepares to deliver a container vessel to the Port of Newark. Ocean Express generates a 358 transmission identifying the vessel in the M10 segment, designates Newark as the destination port in a P4 loop entry, and then creates MBL segments for each of the 200 bills of lading aboard—some containing electronics from Taiwan, others containing apparel from Vietnam. Within each MBL section, optional VID (Conveyance Identification) segments reference specific containers, enabling Customs officials to correlate cargo at the container level. Ocean Express sends this 358 to U.S. Customs and their freight forwarding partner, Custom Clearance Solutions, 24 to 96 hours before arrival, allowing both authorities and the broker to review and flag items for inspection.