This X12 Transaction Set contains the format and establishes the data contents of the Customs Manifest Transaction Set (309) for use within the context of an Electronic Data Interchange (EDI) environment. The transaction set can be used by carriers, terminal operators, port authorities, or service centers to provide Customs with manifest data on cargo arriving in or departing from oceangoing vessels, railroad trains, or other types of conveyances. The transaction set can be also used by carriers to provide terminal operators, port authorities, or service centers with manifest data on cargo arriving at their facilities via the conveyances mentioned above.