Getting to Vieques starts with getting to San Juan. Luckily, this is extraordinarily easy, since San Juan is the hub for the whole Caribbean. Nonstop daily flights are available on several major airlines, all of which fly to San Juan's international airport, Luis Muñoz Marin, code SJU. From there, you have a few options for getting over to the small island.

Most convenient: 

Flights from San Juan to Vieques leave from both SJU and the smaller Isla Grande Airport in San Juan, flights from either take about 25 mins.

It is less expensive to fly to Vieques from Isla Grande than SJU (roughly <110USD r/t vs >180USD r/t). To get directly from one airport to the other, you can take a short, reasonably priced public taxi ride.

For the short flight, guests have their choice between Vieques Air Link, Air Sunshine, Air America Caribbean and several others, the cheapest and best flight from SJU to Vieques on MN Avaition ($75pp each way) and they were very flexible, see this travel guide for a good list: Vieques Travel Guide  

Be aware that sometimes reaching airlines at the Vieques airport by phone can be difficult. Some airlines also require reconfirmation the day before your flight.  

 

It is possible also to take a flight one way and ferry the other , if you would like both experiences. The flight is actually a lot of fun because the planes are small and you have wonderful views of the sea and the islands. The ferry has only one section of outdoor seating, and boarding can be chaotic.  

Least expensive: 

You can take a ferry from the eastern port of Fajardo. Leave plenty of extra time for this. From San Juan you will need to rent a car or take a taxi to reach Fajardo (1 hour minimum driving time, 60-70USD), then the ferry ride is 75 minutesr and costs 2USD. The ferry schedule can be found here: Vieques Ferry Schedule

Most of the time there is no problem arriving 30-45 minutes in advance to buy a ticket. In some cases, depending on the season, arriving late can work to advantage, since the line is gone. But only in some seasons. Sometimes the 9:00 AM Saturday ferry leaving Fajardo can be sold out (due to holidays/weekend travelers) so arrive at ticket office early.  It is rare that the ferry office answers their phone - so buying tickets by phone is usually not an option.   Do not try to take a rental car on the cargo ferry  (insurance would not becovered in Vieques and reservations are very diffcult to obtain).

 

If the ferry is not running (mechanical problems, weather, etc) then go to the Ceiba airport,, not far from the ferry terminal in Fajardo, where there are flights to Vieques (12 minutes) for approximately $26USD.  To reserve this flight call  Vieques Air Link in Ceiba.