On a trip to some of Costa Rica's parks couple years ago I had a free day near Quepos on the SW coast. The afternoon before I went to the main dock, managed to find a boat going out next day, and split the cost with two other random singles. We trolled around all day, caught nothing. One guy had a hit on briefly, and we saw a couple sailfish following, but no takes. Highlight of the day was a pod of hundreds of spinner dolphin - leaping in the air and doing their twists. Little ones, big ones, some close to the boat. Amazing scene.
All tackle was supplied - trolling rods. Fun day, but would have been better with a fish or two on the end of the line. I did not have equipment with me. Did not try for any inshore boat fishing arrangements.
Quepos had a sizeable sportfishing fleet.