Caño Negro, and 1 1/2 hours drive from Arenal is an immense inland lake that is home to the largest tarpon you're likely to find in the country. Largest actually weighed-in from there was 205 pounds. There is also snook, drum, guapote, and others.

Lake Arenal is open to fishing throughout the year, but there are closed seasons in most inland waters, and a valid Costa Rican fishing license is required for fishing in the country. Most guides and resorts catering to fishermen will provide the license as part of their packages.

Parismina Arenal Aguila de Osa San Juan River Tamarindo Ocotal Costa Rica and Nicaragua Fishing

GUIDE TO SEASONS IN KEY FISHING AREAS

PACIFIC COAST - The Pacific Coastal region is divided roughly into the Northern, Central, and Southern fishing areas, with conditions varying with the seasons in each area.
In the Northern Pacific, Flamingo Beach, with a full-service marina, is the major sport fishing center, but boats also charter out of nearby Coco's beach, Tamarindo, Ocotal, Potrero, Brasilito and a few points in between.
A bit further south, there are boats operating below Cabo Blanco, out of Nosara, Garza, Samara and Carrillo beach, a region that gets more protection from the winds that normally blow late December into March and April.
In the Central Pacific, October is normally the top month for Marlin, but action is also good in September and November and occasional blues and rare blacks are likely to be found anytime of year. Middle of December to the end of April -when they begin moving north- is rated the best season for sailfish, but the big schools often move in about October and occasionally stay longer. A few sails always show among the catch from June through September, mixed with the other species that are found inshore during those months.
In the Southern Pacific, August through December is the peak season for Marlin, but an occasional striped, blue or black may be taken most any month if the water temperature is up.
A few Sailfish can be taken off and on year round with best fishing from December through march. It often slows from April into early June, then picks up again and peaks in August and September.

Northern Pacific
(Cabo Blanco to the Gulf of Papagayo)

• Marlin - Every month of the year, with mid-November to early March exceptional.
• Sailfish - Caught throughout the year, with May through August normally the top season.
• Tuna - Peak months are probably August through October
• Dorado - More commonly known as "dolphin", are most abundant from late May through
• October when the seasonal rains flood the rivers.

• Marlin - October is normally the top month, but action is also good in September and November.
• Sailfish - Middle of December to the end of April.
• Tuna - Found throughout the year but most abundant from about June to September.
• Dorado - Best action begins with the winter rains that start in late May.

• Marlin - August through December is the peak season.
• Sailfish - A few taken on an off year-round with the best fishing from December through March.
• Tuna - Best fishing for yellowfin tuna corresponds with marlin and sailfish season.
• Dorado - Best runs are traditionally from late May through October.

• Tarpon - Always around, with traditional high season from December through May, but that was a number of years ago when all of the lodges were fishing with smaller boats and couldn't get outside the river mouths.
• Snook - Generally peaks from March through May again September through the end of November.
• Billfish - Atlantic sailfish and occasional Atlantic blue marlin most anytime of the year. Most are caught from February through September.
• Wahoo - Early February through mid June
• Dorado - Throughout the year.
• Tripletail - January through June

Parismina Arenal Aguila de Osa San Juan River Tamarindo Ocotal Costa Rica and Nicaragua Fishing