Autoridad de Transporte Marítimo. Carr De Maternillo, Fajardo, n/a Puerto Rico, 00740. 787/494–0934; www.dtop.gov.pr.
Service is from the ferry terminal in Fajardo, about a 90-minute drive from San Juan. There are a limited number of seats on the ferries, so get to the terminal in plenty of time. One-way tickets are $2 for Vieques and $2.25 for Culebra.