31 CFR §515.550

1. (a)Unless a vessel is otherwise engaging or has otherwise engaged in transactions that would prohibit entry pursuant to § 515.207, § 515.207 shall not apply to a vessel that is:
   1. (1)Engaging or has engaged in trade with Cuba authorized pursuant to this part;
   2. (2)Engaging or has engaged in trade with Cuba that is exempt from the prohibitions of this part (see § 515.206);
   3. (3)Engaging or has engaged in the exportation or reexportation to Cuba from a third country of agricultural commodities, medicine, or medical devices that, were they subject to the Export Administration Regulations (15 CFR parts 730 through 774) (EAR), would be designated as EAR99;
   4. (4)A foreign vessel that has entered a port or place in Cuba while carrying students, faculty, and staff that are authorized to travel to Cuba pursuant to § 515.565(a); or
   5. (5)Carrying or has carried persons between the United States and Cuba or within Cuba pursuant to the authorization in § 515.572(a)(2) or, in the case of a vessel used solely for personal travel (and not transporting passengers), pursuant to a license or other authorization issued by the Department of Commerce for the exportation or reexportation of the vessel to Cuba.
2. (b)Unless a vessel is otherwise engaging or has otherwise engaged in transactions that would prohibit entry pursuant to § 515.207, § 515.207(a) shall not apply to a foreign vessel that has engaged in the exportation to Cuba from a third country only of items that, were they subject to the EAR, would be designated as EAR99 or would be controlled on the Commerce Control List only for anti-terrorism reasons.