I spent May 21 thru 25 at the Silver King Lodge at Barra del Rio Colorado, Costa Rica fishing for tarpon and (as it happened) Jacks. The accommodations were comfortable and the meals first rate. More to the point, the fishing was excellent.
In four and one half days of fishing, I jumped approximately 20 fish and boated seven--five tarpon and two Jacks. The tarpon ranged from 50 to 175 lbs. and the Jacks were each about 30 lbs. Clifford Ramos Loria, (506) 8841-02-30, was my guide, and he's the one you want for fly fishing.
I used a TFO Bluewater MD 14wht. rod with a Tibor Pacific reel loaded with an Orvis 600 grain Depth Charge line. I tied the flies on Gamakatsu 2H 5/0 hooks. All the tackle performed flawlessly.
The best months to fish are May and esp. September and October. The big tarpon stack up at the mouth of the river in the fall.
RoseAnne Cody manages the lodge. You can reach her at (978) 335-0755 and firstname.lastname@example.org