Jaco is the go-to for surfer and beach lovers, and is the closest beach to the capital of San Jose. It might not be the cheapest beach in Costa Rica, and its probably the most visited beach in Costa Rica, but there is a good reason for it. The beach is world class and beautiful. The town is relatively big for Costa Rica, meaning there is a lot more to do when it comes to excursions, nightlife, water sports, and eating. I personally enjoyed a guided ATV tour of the beaches and surrounding hills and jungle, a very long zip-line trip, some great diving and snorkeling, and some awesome seafood.