Fly-Fishing 101: Things to Know About Fly Lines

Fly lines for every application, spooled, labeled and ready to roll Fly lines for every application, spooled, labeled and ready to roll.

In conventional fishing, the weight of a lure carries the line. But in fly-fishing, the weight of the line casts and delivers the fly. So, in order to go fly-fishing—no matter if you’re after freshwater or saltwater species, and no matter the fly—you’ll need a fly line to get your offering to a fish.

 What does the fly line do?

The basic purpose of a fly line is to carry the fly when it is cast or propelled with the aid of the fly rod. In general, flies do not have enough mass to be cast like lures. The fly line is what carries the fly when a cast is performed. That’s what makes it fly-fishing.

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What weight fly line do I need?

A fly line’s weight always corresponds to a fly rod’s weight. So, in order to balance a fly rod you’ll need a fly line that matches the rod’s designated weight. For instance, a 5-weight fly rod pairs with a 5-weight fly line. A 9-weight fly rod pairs with a 9-weight line, and so on. The weight or mass of the appropriate line bends the rod on the back and forward motions of a cast. When the rod motion is stopped, the stored energy releases, much like an arrow works with a bow, propelling the fly line, leader and fly to its full length. In simple terms, a properly matched fly line should balance and load your fly rod and be relatively easy to cast. As a general rule, the larger the fly line size, the larger the fly it will cast and the larger the fish it is designed to land.

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Are all fly lines built the same?

Nope. Not even close. Manufacturers offer multiple category price points. Standard lines are generally under $50. Premium and specialty lines run from $75 to $100. Ultra-premium lines exceed $100. Every season, more categories and options appear on the market.

Why the variance in cost? Materials, design, coatings, textures, research and development, and so forth. The good news is that a $40 fly line gets the job done nicely, in most cases, for most anglers.

Are there different types of fly lines?

Lots. There are trout lines, bass lines, pike lines, salmon lines, bonefish lines and tarpon lines. There are lines designed for rivers and lines designed for lakes. There are fly lines that float, sink slowly and sink quickly. There are fly lines designed for delicately presented small dry flies, and fly lines designed to throw 12-inch long flies for large, predatory gamefish. I could go on and on, but to keep it simple, let’s start with the most universal fly line for the most popular sized fly rod—if you are setting up a 5-weight fly rod, you are generally starting with a WF5F, line which stands for a weight-forward (WF) 5-weight (5) floating line (F).

Years ago, fly lines were produced with a level diameter. While it is possible to cast with a level line, designs have gotten better. A weight forward fly line is shaped more like a bullet; it starts with a narrow tip and builds mass going rearward. The increased rear mass provides more push when the line is propelled. The weight forward, or head, portion is generally between 30 and 50 feet long. This is within the range of most casting needs. The forward mass easily carries the leader and fly. Behind the weight-forward portion, the line quickly tapers to a much thinner running line. On long casts, the head pulls the thinner running line behind it with less friction than a larger diameter section of line would produce. Simple physics.

Fly line taper

Anglers often ask a lot from their fly lines. Just like any tool, a particular fly line is best suited to a particular application. What makes fly lines suited for a particular task is their taper. We have discussed the weight-forward taper, but now let’s look at two more examples.

If we deliver a small fly over calm water and we want it to land without disturbance, we need a relatively long, gradually thinning taper to dissipate the energy of the cast, so the fly lands softly. Conversely, if we are casting a large, wind-resistant and/or heavy fly, we need a short, thick, aggressive taper that provides a maximum amount of energy transfer and efficiently casts that bulky fly. These examples are two extremes. Anglers have many fly-line tapers to choose from and each serves specific needs. Most beginners meet in the middle and start with a standard weight-forward trout style line for their first setup, and that serves them well in most instances.

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Choices, choices

Taper is only one factor to consider when choosing a fly line. Fly lines continue to advance and cover just about any situation and match up with any fly-rod design. Fly lines come in different densities, textures, lengths and styles. There are lines designed for cold water and lines designed for hot, tropical conditions. There are lines designed for 6-foot long fiberglass rods targeting 20-foot casts, and lines designed for 16-foot long, two-handed graphite rods that cast out to 150 feet.

Beyond floating lines, fly lines can have light, medium or heavy-sinking portions of varying lengths. Some fly-line systems are constructed with multiple parts; running lines, heads and tips can be mixed and matched by looping the sections together, creating a customizable system that is quickly adaptable to various needs. It’s important and exciting to note that the possibilities for refinement are almost endless. Fly anglers can build a collection of perfect tools for their fly casting needs . . . but, you don’t have to. Remember, a weight-forward floating line handles most situations and certainly gets you started in the sport.

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Don’t worry. It’s really easy.

Your local fly shop is a great place to start when searching for a fly line. Just make sure you know the line weight of your fly rod. Better yet, bring your rod in, along with a reel. With a few questions about where you will fish, the species you want to pursue, and the type of flies you expect to use. That info should make it easy for one of our fly-shop experts to match your rod with the best line for the job.

Fly Line Terminology

*Grains: Grains are a standard unit of measure or weight for a fly line.

*Head: The head portion of the fly line consists of the front taper, belly or body and the rear taper.

*Running Line: The running or shooting line is a thinner level portion behind the head. Running line is generally not carried in the air during a cast, but follows or shoots out behind the head on a longer cast.

*Taper: The taper is the shape of a fly line.

*Tips: Tips are added to the head or body of a fly line to either complete the taper or add a different characteristic, such as a sinking portion.

*Loop: A loop is a just that—a loop at the end of the fly line that matches with the end loop on a leader and makes attaching leaders to the fly line, or changing leaders, easy.