Before we consider the best fly line for trout lets look first at what we should do to make sure we have the correct fly line for the task. There are so many ways to fly fish for trout that we need to look at these permutations before purchasing a fly line.
For example we can fish in rivers, still waters or the sea. The target species can be very different too as small lough trout on an Irish moorland would be slightly different to fly fish for than steelhead in a river or river returning sea trout on the Rio Grande. However for the purpose for this article lets consider fishing for brown trout in a river, rainbow trout in a lake and sea trout on the Rio Grande to help with some of those permutations.