The local bus leaves 4-5 times a day direct from Caribe Station in San José. Last bus leaves at 4PM and all buses are direct with one pit stop outside of Limon. The ride is approx 4 hours. Make sure you get on the bus to Puerto Viejo de Talamanca, not de Sarapiquà which is a different part of the country.
If you want to save a few colones, you can take local bus from Caribe station to Limón and transfer to Puerto Viejo bus. This is what many locals do.
There are also tourist buses that will pick you up at your hotel and drop you off where you want. The most popular one is Easy Ride Shuttle Services they run daily from San Jose hotels to Puerto Viejo at 10.00 am returning daily at 3.30 pm rate is $40 one way per person. There is also Grayline.
Driving here is also popular, but roads can be bad as at certain times of the year, the pot holes can get obnoxious. However, you really don't need a car when you are here. Most people rent bicycles and scooters. The roads may not be all paved, but they are flat as they all follow beach line.
