19 CFR § 4.80a - Coastwise transportation of passengers.
(a) For the purposes of this section, the following terms will have the meaning set forth below:
(1) Coastwise port means a port in the U.S., its territories, or possessions embraced within the coastwise laws.
(2) Nearby foreign port means any foreign port in North America, Central America, the Bermuda Islands, or the West Indies (including the Bahama Islands, but not including the Leeward Islands of the Netherlands Antilles, i.e., Aruba, Bonaire, and Curacao). A port in the U.S. Virgin Islands shall be treated as a nearby foreign port.
(4) Embark means a passenger boarding a vessel for the duration of a specific voyage and disembark means a passenger leaving a vessel at the conclusion of a specific voyage. The terms embark and disembark are not applicable to a passenger going ashore temporarily at a coastwise port who reboards the vessel and departs with it on sailing from the port.
(5) Passenger has the meaning defined in § 4.50(b).
(b) The applicability of the coastwise law (46 U.S.C. 55103) to a vessel not qualified to engage in the coastwise trade (i.e., either a foreign-flag vessel or a U.S.-flag vessel that is foreign-built or at one time has been under foreign-flag) which embarks a passenger at a coastwise port is as follows:
(2) If the passenger is on a voyage to one or more coastwise ports and a nearby foreign port or ports (but at no other foreign port) and the passenger disembarks at a coastwise port other than the port of embarkation, there is a violation of the coastwise law.
(3) If the passenger is on a voyage to one or more coastwise ports and a distant foreign port or ports (whether or not the voyage includes a nearby foreign port or ports) and the passenger disembarks at a coastwise port, there is no violation of the coastwise law provided the passenger has proceeded with the vessel to a distant foreign port.
(c) An exception to the prohibition in this section is the transportation of passengers between ports in Puerto Rico and other ports in the U.S. on passenger vessels not qualified to engage in the coastwise trade. Such transportation is permitted until there is a finding under 46 U.S.C. 55104 that a qualified U.S.-flag passenger vessel is available for such service.
(d) The owner or charterer of a foreign vessel or any other interested person may request from Headquarters, U.S. Customs and Border Protection, Attention: Cargo Security, Carriers & Immigration Branch, Office of International Trade, an advisory ruling as to whether a contemplated voyage would be considered to be coastwise transportation in violation of 46 U.S.C. 55103. Such a request shall be filed in accordance with the provisions of part 177, CBP Regulations (19 CFR part 177).