Getting to San Juan del Sur is really easy. It is one of the easiest beaches to get to in all of Nicaragua.
The first thing to do is get a flight into Managua. Many airlines (such as Delta, Taca, Copa Airlines, and Lacsa to name a few) have direct flights during peak tourist season from all over the world including Canada, The United States, Cuba, Germany, and Mexico. During low season, you may need to bounce around a bit to make your way to the Managua airport.
Once you are away from the airport there are a few choices for getting to san Juan del Sur:
Airport Shuttle: The Airport shuttle is the number one choice for a lot of travelers for convienence and cost. There are many airport shuttle companies right on site at the airport making the cost a little bit more economical than a taxi. Also, unlike a taxi, a lot of Airport Shuttle drivers speak intermediate English which makes it easier on those of you who may not speak Spanish. The cost for an Airport shuttle ranges from $65 to $100 depending on the number of people in your party and the shuttle you choose to go with. A nice thing about airport shuttles as well is that they may have some tips about where to stay or what to do whn you get to San Juan del Sur.
Taxi: You can take a taxi right from the airport to San Juan del sur, which provides a private experience and may be for you if you don’t like having to deal with crowded buses. Also if you have a lot of luggage you may wish to consider this option as well. A taxi will cost you a lot, anywhere from $75 to $200 depending on the number of people in your party, how much luggage you have, and of course how greedy the taxi driver is. Some Taxis may speak a little English, but the majority of them will speak only Spanish with one or two key words they have learned in English. It is important if you go with a taxi to make sure it is a legal one. Check to make sure it has plates that are red and white around the border, has a checkered yellow or white fringe and to be on the safe side has some sort of alliance with a taxi company. NEVER go in a taxi without licence plates!
Bus: Taking the bus is a real experience. You will get to meet locals from Nicaragua as well as travelers from all over the world such as yourself.
Rent a car: Or of course if you know where you are going exactly, and feel comfortable driving in Central America (You would be one of the few!) you can always rent a car to go to San Juan del Sur. This is convienent because you can make your own schedule. It costs in the vicinity of $45 per day for a rental care in Nicaragua.