You can reach Culebra via daily ferry from Fajardo or on week days from Vieques. Maritime Transport Authority website for schedule and price information Average price is about $2.50 for a ferry ride and it takes about one to one and a half hours from Fajardo. However, reaching Fajardo from San Juan by taxi costs $80-100. You can also reach Culebra via daily airplane service from San Juan, Fajardo, Vieques or nearby Saint Thomas. This option is the best and easiest way to travel. Air Flamenco and Vieques Air Link has a service that leaves from Isla Grande Airport to Culebra. San Juan Isla Grande airportSIG is approximately a $25 15 minute cab ride from San Juan International airport. These are small 8 passenger planes. The plane ride may cost $60 one way and take 35 minutes. If you are 1 adult this is the better option. If you are two people traveling the taxi from San Juan to Fajardo might be your better option. For 2 adults it would cost approximately $45 per person with cab and ferry one way.
For a budget traveler, you may also want to consider taking one of the local buses to Fajardo. Prices may be negotiated if you speak Spanish, and $10-$20 per person should cover the two to three hour ride. This highway tends to get busy. Check what time the last ferry leaves Fajardo. I believe it is 3pm. The buses are vans that depart sporadically, do not have air conditioning, and primarily serve locals. Tourists may have difficulty persuading taxi drivers that you want to go to the bus station.
It is important to note that although the ferry is a cheap option it is extremely busy during the high season holidays and summer months. During these times the ferry will be extremely hard to use as people camp out as early as 4 in the morning for tickets. I would recommend taking a flight to avoid the hassle of the very and the chance of not being able to get to the island.
