46 U.S.C. § 55103 — Transportation of passengers

(a) In General. Unless this chapter or chapter 121 says otherwise, a vessel can't transport passengers between U.S. ports or places covered by the coastwise laws — even by way of a foreign port — unless the vessel: (1) is entirely owned by U.S. citizens for coastwise-trade purposes; and (2) either has a coastwise-endorsed certificate of documentation under chapter 121, or is exempt from documentation but would otherwise qualify for that certificate and endorsement. (b) Penalty. Breaking this rule costs $300 for every passenger the vessel transports and lands.