International flights go directly to Samana International Airport. From the airport to Las Terrenas, cab drivers will ask for $70 US dollars. Check with your hotel and see if you can get a better deal. The ride is a bit rough and takes about 45 mins.
Guagua routes exist from Santo Domingo (express guagua), Sanchez, and Samana. If you feel adventurous, you can also take a pickup truck or a motoconcho (with trailer) from Samana over the mountains.
The express guagua to and from Santo Domingo takes 2.5h if there is no traffic. Traveling with guaguas and ferry from Punta Cana to Las Terrenas will take about 8h, but is certainly possible within one day.
New taxi service in Las Terrenas area. Las Terrenas Taxi www.LasTerrenasTaxi.com offers pick up and drop off at all airports in the Dominican Republic.
Private Plane Service around the island use Punta Cana Plane Charters. http://www.puntacanaplanecharters.com/
Motorconchos or motortaxis The cheapest mode of transportation may be motoconchos. Going from downtown to Playa Bonita, about 4 km, cost about 50 pesos per person, and can take two passengers. In the evening, the price may go up. In 2010, at least, it seems that anyone with a motor bike can be a cab driver. So it's really easy to get a ride. Taxi to and from airport contact Las Terrenas Taxi. www.lasterrenastaxi.com
Guagua or collective taxis You can catch Guaguas in downtown and they can go a greater distance, ex. to the waterfall in El Limon.
Scooters or 4x4 You can rent a scooter for about $20 US per day or a 4x4 for about $55 US. Rentals can be arranged in most hotels but there are also rental locations in downtown Las Terranas. These modes of transportation seem most common for visitors. Locals use motorcyles or cars. Drivers will have to pay special attention to potholes especially at night or after rain. You can go to the waterfall in El Limón on a scooter. It takes about 45 mins.
Pueblo de los Pescadores. http://www.pueblo-de-los-pescadores.com/