How Do I Choose a Fly-Fishing Line?

Your fly-line selection should typically match your rod weight and the style of fly fishing you intend to use it for. Look at all the qualities of each type of line and ask yourself if it matches your intent. Try testing out the lines by casting several of them to see which line matches your style and specific needs the best.

Cast Before You Buy

Before you choose a fly line, you’ll need to choose a rod. The best starting point for choosing a line is to know the line weight the rod was designed to cast—for example, a 5WT (5-weight) rod is designed to cast a 5WT line. But there is a lot of gray area in that rule, as what casts “best” is subjective, and anglers have different preferences.

Once you have a rod in hand, then the decision-making process can begin as you test different lines with it.

The more lines you try for your rod, the more informed a buying decision you can make. After casting a 6WT line on a 5WT rod, you may find that it matches your casting stroke better. Or, perhaps you prefer a textured fly line versus a smooth line, or vice versa.

Sinking lines can be a bear to cast, and you may not enjoy using all of them. Some may be better suited for you than others.

While the dozens of different types of lines all have their place, the most common lines for fly fishing are Weight Forward (WF) lines matched to your fly rod weight. And that’s all you’ll need to get started.

If you have a 5WT fly rod, a floating, WF5 (weight-forward, 5-weight) line will handle almost all the fishing you will do. If you’re using an 8WT fly rod for striped bass fishing, an intermediate sinking 8WT fly line will work well.

Try Different Fly Lines for Different Situations

In addition to knowing the weight of fly line you’re interested in, you’ll want to choose either a freshwater or saltwater line. Then, you’ll want to decide on the type of fly line.

These are the most common fly lines you’ll encounter:

• Floating Fly Lines: These are arguably the most common fly line, especially for beginner anglers. The line is designed to float on the water, which helps keep your flies on the surface or high in the water column, while reducing drag. They’re extremely versatile, and they’re the preferred fly line for fishing dry flies, emergers, and nymphs. And while they’re not ideal for streamers and wet flies, many anglers fish those flies successfully with a floating line (they may just require a little added weight on the fly and/or the leader). 
• Sinking Fly Lines: As the name implies, sinking fly lines are designed to sink in the water column. The entire length of a sinking line is designed to sink at a specific rate, making it more popular for fishing still water, like lakes. These lines are rated for how far and how fast they sink in water: inches per second (IPS). This rating allows you to calculate how far down your fly should be sinking as you count the number of seconds it’s in the water. For instance, if you cast a nymph on a slower-sinking 1.5 IPS line into still water, every second you count, you can expect that nymph to have sunk another 1.5 inches in the water. Some sinking lines, like the Orvis Depth Charge, have different sink rates along the length of the line, performing more like a sink-tip fly line.
• Sink-Tip Fly Lines: These fly lines are like a hybrid of a floating line and a sinking line, with the weighted sinking section at the leader end of the line. This allows your running line to sit on the surface, while the leader end will sink and pull your leader and fly down in the water column. River anglers prefer sink-tip fly lines for fishing streamers, especially in fast, heavy water. The sink tip will get the fly down deep where the baitfish, or other prey it imitates, lives, while the floating running line stays on the surface and out of the way of snags and obstacles in the river.

While these are the most common types of fly rods, you may encounter other subtypes, including:

• Skagit or Spey: These lines are designed with powerful tapers for this type of casting and the rod associated with it. It’s a popular salmon and steelhead method, though there are many trout Spey anglers out there, too. 
• Tactical or Euro Nymph Lines: Since tactical nymphers cast less fly line, tactical nymphing lines are thin to reduce snags when casting and improve sensitivity, helping you tell the difference between bumping bottom and an eat. 

Breaking the Fly Line Rules

The weight rating on a fly line does not mean you could not cast the fly line with a mismatched weight rod. You can cast a 6WT line on a 5WT rod. The reason a 5WT line casts best on a 5WT fly rod is that the line is tapered and constructed specifically for that type of rod.

But there may be situations where a larger line may help you. For example: Say you’ve spent three hours casting weightless dry flies to rising fish. After catching a few fish, you’ve got to be on your way home soon.

Before winding up and calling it quits, it may be worth it to “swing for the fences” and swim a streamer through the hole. Unfortunately, simply clipping off your dry fly and tying on a large streamer won’t work as well as it could. Your line won’t turn over easily and you might have trouble controlling your casts. An alternative option is to reline your rod with a larger line weight and taper (typically one size up).

A ground rule and the best place to start is to match your line to your rod’s weight, along with the water type and fly types you plan to fish. Fly casting should be a pleasure and not feel cumbersome. You shouldn’t have to put extra effort into any part of the cast to get your flies to turn over, and a line matched to your rod and your casting style should help make your casts accurate and effortless.