Fly Fishing for Jack Crevalle

Fly fishing for Jack Crevalle often takes a backseat to more well-known species like tarpon, but on this trip to the Rio Colorado in Costa Rica, they completely stole the show. Normally, we’d land a handful over a week, but this time, we were catching that many in a single session. Their raw power and relentless fight never get old—pound for pound, they are some of the hardest-hitting fish you can target on a fly.

A Passion for Jacks

Xuan, one of three anglers from China who joined me during the first week, quickly became obsessed with these jacks. A seasoned trevally fly fisherman, he had plenty of experience chasing Giant Trevally but had never targeted Jack Crevalle. From the moment he hooked into his first one during the lower phase of the tide, his excitement was contagious. With every fish, his grin grew wider.

What stood out most was how much he enjoyed these battles, perhaps even more than the tarpon he landed. And he caught some absolute giants—more on that in a future post.

Adapting to the Bite

Midway through the week, the current slacked off, and the bite changed dramatically. The usual blistering takes—where it felt like you’d foul-hooked a freight train—became more subtle. Instead of explosive runs right from the start, the jacks would tap the fly lightly before launching into chaos once hooked. This shift threw off some of the other guests, but Xuan had already fine-tuned his technique.

His approach was methodical: a long cast, a couple of mends, let the line tighten, pause, then a slow strip… tap, tap, tap—set! The moment the hook connected, the water would erupt, the line would carve through the surface, and just like that, he was deep into another battle. Watching him execute this process so precisely never got old.

Best Tackle Setup for Jack Crevalle

To get the most out of these fish, a solid setup is key:

• Rod: A 12wt fast-action fly rod provides the backbone needed for these bruisers.
• Reel: A reliable saltwater reel with a strong drag system is essential.
• Line: An intermediate fly line works well, but depending on the current and depth, carrying a sink-tip option is a good idea.

A Week to Remember

By the end of the week, I had lost track of how many jacks we landed—not that the number mattered. Some fish leave an impression well beyond the count, and this trip was a perfect example of that.

If you haven’t experienced fly fishing for Jack Crevalle, now is the time to add them to your target list.