Quepos is one of the best billfish ports in the world, and the Marina Pez Vela is where the boats are. Costa Rica Fishing Company runs private charters offshore for sailfish, marlin and tuna, and inshore for roosterfish and snapper — the inshore days are cheaper, shorter and better for people who are not sure they want eight hours at sea.
Peak billfish season is roughly December to April, though something is biting year-round.