Puerto Viejo is located on the Caribbean side of Costa Rica and it is the main tourist hot spot for that side of Costa Rica. You will find yourself in flip flops walking down jungle roads to small restaurant and bar hideaways. Reggae music fills the scene here as its heavily borrowed from the near by Caribbean islands. It is widely known for its heavy yet good reef break surf spots. Any day you might find about 5-6 people on the most popular breaks. Surf lesions are widely available in this area and any hotel or restaurant can point you in the direction of where to catch that.
If your adventurous and plan of going to panama, Puerto Viejo is a perfect place to stop before you head for the boarder. Panama customs hold the boarder in this area and its a perfect crossing point. The town of Puerto Viejo is made up of native Costa Ricans, Jamaican population and many Europeans the have emigrated to this area. Aside from the hotels in this area most of the homes run off the grid and get water from towers on their land. So you can expect accommodations to not exactly be 5 star type hotel treatment. However that is part of the adventure in this area and it works for what it is. Most of the hotels will have mosquito nets around the bed and some hotels are even out doors. There is plenty of wild life in the area and you might even catch site of a wild Macaw or two.