Port and Maritime Security bill

Port Threat and Security Act - Directs the Secretary of Transportation to report to specified congressional committees: (1) a list of all nations whose flag vessels have entered U.S. ports in the previous year, and of those nations, a separate list of nations whose registered flag vessels appear as Priority III or higher on the Boarding Priority Matrix, that have presented certain false vessel-related information to the United States, or whose laws or regulations are not sufficient to allow tracking of ownership and registration histories of registered flag vessels; (2) on actions taken by the United States to improve transparency and security of vessel registration procedures in nations that have been listed; and (3) on recommendations for legislative or other actions needed to improve security of U.S. ports against potential threats posed by flag vessels of such nations.

Establishes a program to place sea marshals on vessels entering U.S. ports that have been identified as posing a potential target of attack or because of their location may pose a risk to residential or other densely populated areas.

Directs the Secretary to assess the effectiveness of security measures maintained at foreign seaports that serve U.S. vessels, from which foreign vessels serve the United States, or that pose a high risk of introducing danger to international sea travel. Sets forth certain actions the Secretary must take against seaports that do not maintain effective security measures.

Imposes a user fee on cruise vessels that arrive at a U.S. port from a foreign port.