May offshore bite in Costa Rica boosts yellowfin tuna chances

Yellowfin and mahi are both on the menu

The late-May bite off Los Sueños, Jacó, and Herradura is giving anglers the kind of decision that actually matters: do you chase meat, billfish, or both. Adventure Tours Costa Rica’s May report, dated May 15 and updated through May 19, puts mahi-mahi, yellowfin tuna, and billfish at the top of the offshore board, with the strongest action building in the second half of the month.

That matters because this is not being sold as a pretty fishing report, it reads like a planning tool. The message is simple: if tuna is the goal, the window is open now, and the smartest way to spend it is with an early start, a full-day offshore run, and enough range to work current lines, floating debris, and any patch of clean blue water that lights up with activity.

The best day starts early and runs long

Morning departures are the most reliable play in this green-season pattern. The report says the showers usually build later in the day, which means the first stretch offshore is the one you want to protect for trolling, searching, and making quick moves when the water tells you where the fish want to be. If you’ve ever watched a good early bite get buried under weather by lunch, you already know why that detail matters.

That timing also shapes how you should think about the trip itself. A full-day offshore charter is the best fit if tuna, mahi, and marlin are the priority, because it gives you time to work the spread over productive water instead of burning the first half of the day just getting there. For anglers who only have a shorter window, half-day or three-quarter-day inshore trips make more sense, but those are built more for roosterfish and snapper around points, reefs, and river mouths than for a serious yellowfin hunt.

If you only have one trip, make it the offshore one

If you’re flying in for one day and want the highest-value shot at a tuna box, book the offshore day first. The report is clear that the offshore bite is where mahi and yellowfin are showing strongest, with consistent shots at marlin and sailfish layered in behind them. That is the kind of spread that turns a single trip into a real mixed-bag day, especially if the fish are stacked on debris or along current breaks.

The inshore option is practical, and it has its place, especially for families or groups that want a shorter day closer to land. But if your priority list starts with yellowfin and mahi, then the inshore run is the compromise, not the target. The report’s logic is blunt: choose the boat and the trip length that matches the fish you want, not the other way around.

• Best tuna plan: full-day offshore, early departure, committed range.
• Best mixed-bag plan: offshore again, because mahi, yellowfin, and billfish can all show on the same run.
• Best shorter day: inshore, if roosterfish and snapper are the real goal.

This run is part of a bigger May pattern

The second-half-of-May report is not describing a sudden hot streak. A first-half-of-May update from the same publisher said the month opened fast, with peak mahi-mahi and wahoo action alongside steady offshore bites for marlin, sailfish, and yellowfin tuna. Put together, the two reports show a month-long offshore pulse, not a one-day fluke.

That broader run fits what anglers already expect from this corner of Costa Rica when the Pacific season is moving well. The 2026 Offshore World Championship in Quepos ran April 19-23 with 38 teams from 22 countries and a $232,220 purse, a reminder that the region’s bluewater reputation is not marketing fluff. On the Los Sueños side, the 2026 Triple Crown’s Leg III produced 2,491 sailfish releases, and Team Galati won the overall title with 26,500 points. When the tournament numbers look like that, a late-May report calling for tuna, mahi, and billfish is not surprising, it is exactly what you would hope to hear.

Why Los Sueños and Herradura keep producing

The reason this zone keeps showing up in serious offshore conversation is the geography. Guides and regional fishing coverage in 2026 point to the continental shelf dropping off quickly offshore, which shortens the run to productive water and makes Los Sueños, Jacó, and Herradura efficient launching points for bluewater fishing. You do not need to spend the whole morning grinding your way to where the fish live.

That speed to structure is a big part of why the area has become such a dependable tournament and charter base. Herradura Bay, Los Sueños Marina, and the surrounding Pacific grounds consistently offer a mix of pelagics and nearshore options, but late May clearly tilts the smart money toward bluewater. If you are trying to maximize one trip, the cleanest logic is to start early, stay offshore, and give yourself enough time to let the tuna find you instead of rushing the decision.

The opening hook here is still the right one: yellowfin and mahi are both on, and the best chance to turn that into fish in the box is a dawn departure on a full-day offshore run before the afternoon weather stacks up.