# Big yellowfin tuna on the Southern Pacific

> Costa Rica's far south is one of the best places in the country for a big yellowfin tuna: school fish of 20 to 60 pounds come close to shore, and offshore fish of 100 pounds and more are caught under spinner dolphins and around floating logs. The best months are about May to August, with big fish again late in the year, and boats leave from Puerto Jiménez, Golfito, Zancudo and Drake Bay.

Source: https://sportfishing-costarica.com/southern-pacific-yellowfin-tuna/
Last checked: 2026-11-15
Species: yellowfin tuna (Thunnus albacares), atún aleta amarilla
Typical sizes: 20 to 60 pound school fish; offshore fish of 100 to 250 pounds
Best months: about May to August; big fish also reported November to January
How they're found: spinner dolphins, diving birds, floating logs and weed lines
Where: from the mouth of the Golfo Dulce out to the shelf edge and seamounts, 30 to 70 miles
Keeping one: allowed; 5 fish per trip for your own use, no selling
Bases: Puerto Jiménez, Golfito, Playa Zancudo, Drake Bay

## The short answer

If you want a really big yellowfin tuna in Costa Rica, the far south is the place to try. Off the Osa Peninsula and the mouth of the Golfo Dulce, deep water comes close to shore, huge schools of spinner dolphins roam the offshore grounds, and the tuna travel with them. Crews here catch school fish of 20 to 60 pounds near the coast and offshore fish of 100 pounds or more, and the odd one is bigger still.

This article is all about those tuna: how big they get, when they're here, how crews find and catch them, and what you can keep. It builds on our [complete guide to fishing the Southern Pacific](/southern-pacific-fishing-guide/), which covers the towns, marinas, outfitters and getting there, and our [yellowfin tuna species page](/yellowfin-tuna/), which covers the fish itself.

## Why the far south grows big tuna

Three things come together off the Osa:

- **Deep water close in.** Boats are on offshore water within about an hour of the dock. Crocodile Bay says its boats are fishing offshore 45 minutes to an hour out of Puerto Jiménez, and The Zancudo Lodge puts its grounds about 45 minutes away. The farthest trips run 30 to 70 miles out to the shelf edge and the seamounts.
- **Dolphins.** In the eastern Pacific, yellowfin often travel with schools of dolphins, and the south has a lot of spinners. NOAA Fisheries notes that yellowfin gather around dolphins, drifting debris and other large animals.
- **Rain.** The far south is the wettest part of the Pacific coast. From about October, rivers wash logs, branches and weed lines out to sea, and floating debris holds bait, dorado and tuna.

The fish grow fast. NOAA says Pacific yellowfin reach about 6 feet and 400 pounds, live 6 or 7 years, can breed from about age 2, and spawn all year in tropical water. The all-tackle world record, a 427-pound fish caught off Cabo San Lucas, Mexico in 2012, shows what the eastern Pacific can produce.

![A large yellowfin tuna charging through a ball of small silver baitfish in clear deep blue water](/static/img/spyft-ai-tuna-bait-ball-800.webp)

## How big are the tuna here?

Size depends on where you fish and when. Here's what the people who fish these waters report.

| Source | Where | What they report |
|---|---|---|
| Crocodile Bay | Off Puerto Jiménez | School fish of 20 to 60 pounds near the coast in April; offshore fish of 100 to 250 pounds in December and January; fish up to 300 pounds possible at any time |
| On The Water (2013) | Golfo Dulce, June trip | Schools of 40 to 80 pound fish feeding with spinner dolphins |
| Colio Sportfishing | Off Golfito, seamount trips | A yellowfin of more than 130 pounds landed, shown on its site |
| Hook and Barrel (2023) | Off Puerto Jiménez | Fish from "football size to full-grown" feeding on bait balls |

For comparison, the biggest yellowfin weighed at the central Pacific's big Quepos tournaments in 2026 were 184.7 pounds (Pelagic Rockstar, January) and 187 pounds (Bisbee's Costa Rica Offshore, April). A tuna of 100 pounds or more is a fish to remember anywhere in Costa Rica.

Most days, though, the fish are smaller. Football-size tuna of 10 to 30 pounds are the everyday catch, and they're the best eating.

## When to fish for southern yellowfin

Yellowfin are caught off the Osa all year. Our national [fishing seasons guide](/costa-rica-fishing-seasons/) puts the best months at about May to August, and the southern lodges' calendars add a second window late in the year, when big tuna come with the dorado runs.

| Months | Rating | What's happening |
|---|---|---|
| January to April | Good | Sailfish season; Crocodile Bay reports big offshore tuna into January and school fish near the coast in April |
| May and June | Best | Crocodile Bay's calendar pairs these months with spinner dolphin schools full of yellowfin |
| July and August | Best | Tuna with the marlin offshore; the On The Water trip found fast tuna action in June |
| September and October | Good | Rains build; logs and weed lines start to hold dorado and tuna |
| November and December | Good | Crocodile Bay calls these its most consistent tuna months, with large fish among the dorado |

Seas are generally calmest from about December to May. The green season brings afternoon rain and, from about September, bumpier offshore runs, but the mornings are often clear and the floating debris it washes out is what draws the fish.

## Where the tuna are

### Close to shore and at the mouth of the gulf

School-size yellowfin often come right in to the mouth of the Golfo Dulce and along the Osa coast, especially in the drier months. That's when an inshore trip for roosterfish can turn into a tuna chase. A 2015 Sport Fishing report from a Zancudo Lodge trip described yellowfin exploding among dolphins at the surface in the outer gulf. Our [Golfo Dulce fishing guide](/golfo-dulce-fishing/) covers the inshore side of those days.

### Offshore: dolphins, logs and current lines

The bigger fish are usually offshore. Aguila de Osa fishes 20 to 40 miles off Drake Bay and says its captains look for the big spinner dolphin schools on the way out. Osa Tourism's report for November 9 to 15, 2026 rated tuna a good target around dolphins and bait schools, with some bigger fish farther offshore.

### The seamounts and the shelf edge

The longest trips run 30 to 70 miles out. Colio Sportfishing's full-day Blue Water Expedition goes to the seamounts for blue marlin and big yellowfin schools, and Marina Bahía Golfito says its deep-sea grounds reach up to 70 miles offshore. These are long days, often 10 to 12 hours, on a boat with the range and fuel to do them.

![A flock of brown boobies diving into a patch of boiling white water on the open sea, with no land in sight](/static/img/spyft-ai-boobies-diving-800.webp)

## How crews find and catch them

### Finding the fish

Almost every tuna day starts with a search. Crews scan for 3 signs: big schools of spinner dolphins, seabirds diving into the water, and tuna slashing through bait at the surface. Once they find dolphins, a good captain works out which way the school is moving and gets ahead of it, rather than chasing from behind. On The Water described its crew circling wide ahead of the dolphins and waiting for the bait to be pushed toward the boat.

Costa Rica has a regulation on activities involving whales and dolphins (Decreto 32495), and good crews keep their distance. Ask your captain to fish the edges of the school and never drive through the middle of it.

### Live bait

Live bait catches most of the big ones. Crews catch sardines or small bonito on the way out, then slow-troll or drift them near the dolphins or under the birds. Colio says its offshore tuna come on live bait. Costa Rican law requires circle hooks with any natural bait, which also makes for cleaner releases of anything you don't keep.

### Poppers and stickbaits

When tuna are busting bait at the surface, casting a popper or stickbait into the frenzy is the most exciting way to hook one. Fish often hit right beside the boat. When the fish turn fussy, some crews switch to flies, as the Hook and Barrel writer saw off Puerto Jiménez.

### Trolling

Trolling lures around the edge of a school, or along a weed line, finds fish when nothing is showing at the surface. It's also how many tuna turn up by surprise on a billfish day.

### The fight

A big yellowfin doesn't jump. It runs hard and then dives, circling deep under the boat for a long time. The Sport Fishing team lost one after more than half an hour, almost at the boat, and the skipper kept spinning the boat to hold the best line angle. For fish over 100 pounds, crews use heavy stand-up rods with a harness or a fighting chair, so ask your outfitter what it carries before you book a seamount day.

![A heavy two-speed lever-drag fishing reel on a short stand-up rod, set in a rod holder on a sportfishing boat](/static/img/spyft-ai-standup-reel-800.webp)

## Keeping a tuna, and keeping tuna around

### What you can keep

Yellowfin aren't a catch-and-release species in Costa Rica. The fisheries regulation (Decreto 36782) allows 5 fish per trip to be landed for your own use, and sport-caught fish can't be sold. A 200-pound tuna is far more meat than one group can eat, so many crews take a few loins and share the rest with the crew and the lodge kitchen, or release big fish when the boat already has what it needs. Small tuna are better released to grow.

Bleed the fish and put it on ice right away. Fishing lodges in the south, such as Aguila de Osa in Drake Bay, will cook what you bring back, and fresh yellowfin seared rare or sliced raw is the reward for the fight.

![Slices of seared yellowfin tuna with a deep red centre, served on a white plate with lime and sesame seeds](/static/img/spyft-ai-seared-tuna-800.webp)

### The bigger picture

Tuna sit at the centre of a long argument over Costa Rica's offshore waters. A 2014 decree (Decreto 38681) keeps big purse-seine tuna boats about 45 nautical miles from the coast and sets exclusion zones where they can't set their nets, including one around Cocos Island. A 2014 INCOPESCA agreement also bars longliners from fishing with live bait within the first 30 nautical miles of the Pacific coast, because of the sharks, turtles and sailfish they caught. Southern sportfishing crews push hard to keep those protections, and the Golfo Dulce's own rules are covered in our [Golfo Dulce guide](/golfo-dulce-fishing/) and our national [conservation guide](/costa-rica-fishing-conservation/).

::: gallery "Tuna close up: a big yellowfin tagged for research, another coming to the net, and a Golfito sunset after a day offshore"
![Crew holding a large yellowfin tuna on deck as it's fitted with an electronic tag, its gold side stripe and long dark pectoral fin clearly visible](/static/img/spyft-tuna-tagging-800.webp "Photo: [Tagging a yellowfin tuna](https://commons.wikimedia.org/wiki/File:Marquage_d%27un_thon_albacore_(Thunnus_albacares)_(Ifremer_00540-65191).jpg) by Marc Taquet (Ifremer), CC BY 4.0, via Wikimedia Commons")
![A yellowfin tuna splashing beside a boat as it's guided into a landing net, a lure still in its mouth](/static/img/spyft-tuna-landing-net-800.webp "Photo: [Yellowfin tuna at the net](https://commons.wikimedia.org/wiki/File:Capture_d%27un_thon_albacore_pour_marquage_%C3%A9lectronique_(Ifremer_00540-65177).jpg) by Marc Taquet (Ifremer), CC BY 4.0, via Wikimedia Commons")
![The sun setting over the Golfo Dulce at Golfito, with a pelican on the golden water and a forested headland in silhouette](/static/img/spyft-golfito-sunset-800.webp "Photo: [Sunset at Golfito](https://commons.wikimedia.org/wiki/File:Sunset_at_Golfito_-_panoramio.jpg) by Federico Mata, CC BY 3.0, via Wikimedia Commons")
:::

### Tournaments

The far south has no regular tuna tournament right now. Marina Bahía Golfito ran a Tuna Cup on July 15 and 16, 2022, with prizes for the heaviest yellowfin, but we couldn't find a later edition. The zone's main event is the Battle of the Bay each May, which has a gamefish category alongside billfish and roosterfish; see our [tournaments guide](/costa-rica-fishing-tournaments/).

## Who to fish with for big tuna

For a real shot at a big yellowfin, book a full day on a boat built for offshore work. We opened each of these businesses' own websites in November 2026 before naming them, and nobody pays to be listed. More captains, with their booking pages, are in our [Southern Pacific guide](/southern-pacific-fishing-guide/).

**[Crocodile Bay](/crocodile-bay-resort/) (Puerto Jiménez).** The south's biggest fleet, with Strike tower boats for offshore days, and the most detailed tuna calendar in the zone. Guests stay at the Botánika resort on the same grounds.

**[The Zancudo Lodge](/zancudo-fishing-lodge/) (Playa Zancudo).** Contender center consoles fishing offshore about 45 minutes from the lodge's dock, with all-inclusive packages. The lodge has been listed for sale since August 2025 but is still booking, so confirm your dates directly.

**Aguila de Osa (Drake Bay).** A lodge with its own boats, including the *Albatros*, a 31-foot Palm Beach sportfisher, fishing 20 to 40 miles out. Its kitchen cooks what guests keep. [aguiladeosa.com](https://aguiladeosa.com/explore/water/sport-fishing-charters-osa-peninsula-costa-rica/)

**Colio Sportfishing Charters (Golfito).** A 28-foot catamaran from [Fish Hook Marina](/fish-hook-marina-and-lodges/), running full days to the shelf and a 12-hour trip to the seamounts for marlin and big yellowfin, with all billfish released on circle hooks. [coliosportfishing.com](https://coliosportfishing.com/)

**Cazador (Golfito).** Captain Bobby McGuinness's 37-foot Merritt, with a fighting chair, tuna tubes and a live-bait well, recommends a full day for tuna and billfish. [Booking page](https://fishcostarica.com/fishing-charters/cazador-golfito/)

Several more Golfito charters work from [Banana Bay Marina](/banana-bay-marina-in-golfito/), and Osa Tourism in Puerto Jiménez books local boats and posts a weekly report that's worth reading before you go.

## Frequently asked questions

### When is the best time for big yellowfin on the Southern Pacific?

About May to August is the best stretch, with spinner dolphin schools full of tuna. Crocodile Bay also reports big offshore fish from November to January, so late in the year is worth a try too.

### How big are the yellowfin off the Osa?

Most are 10 to 60 pounds. Offshore, fish of 100 to 250 pounds are caught, and Crocodile Bay says fish near 300 pounds are possible.

### Why do crews follow dolphins?

Yellowfin in the eastern Pacific often swim with schools of spinner dolphins. Finding the dolphins, and the birds diving over them, is usually the first step to finding the tuna.

### Can I keep a yellowfin tuna?

Yes. Up to 5 fish per trip can be landed for your own use, and sport-caught fish can't be sold. Many crews keep one or two and release the rest.

### Do I need a full-day trip for tuna?

For the big fish, yes. A half day can find school tuna near the mouth of the Golfo Dulce, but the offshore grounds and seamounts need a full day.