26 U.S.C. § 4471: Imposition of tax

(a) In generalThere is hereby imposed a tax of $3 per passenger on a covered voyage. (b) By whom paidThe tax imposed by this section shall be paid by the person providing the covered voyage. (c) Time of impositionThe tax imposed by this section shall be imposed only once for each passenger on a covered voyage, either at the time of first embarkation or disembarkation in the United States.