Understanding Fly Line Tapers: An Illustrated Guide

Updated: Jun 3

tapered fly line sections

What is a tapered fly line

A tapered fly line has gradual increases or decreases in weight and diameter throughout its various sections. Each change in weight and diameter impacts the speed and power of the fly line when it's cast.

Fly lines need to create energy on the back cast, as well as release energy during the forward cast. Instead of a line that's uniform throughout its entire length, this energy transfer is made easier when sections of the fly line vary in weight and diameter.

If you're unfamiliar with fly lines in general, read the sections:

If you are somewhat familiar with fly lines, jump to these sections:

Click here to see our article about our favorite fly lines

What does a Fly Line do?

Fly lines connect the fly rod to the fly, and help transfer energy between the two. This energy is created by using the weight of the fly line instead of the weight of the fly itself.

To cast a fly line, enough energy must be created to lift and keep the line off the ground/water on the back cast, and enough to bring the line forward to it's target on the forward cast. Before it reaches its target on the forward cast, some/all of the energy needs to dissipate to allow for a delicate landing on the water.

What are the sections of a tapered fly line

  • Running line: The lightest/thinnest section of line that connects to the reel

  • Back taper: The tapered transition section between the running line and belly

  • Body or "Belly": The heaviest and widest section of the line

  • Front taper: The tapered section between the belly and the tip that allows energy to release on the forward cast

  • Tip: The front section that attaches to the leader

What determines how a fly line will perform?

The three things that determine how a fly line will perform are:

  • Weight

  • Diameter

  • Taper design

When deciding which fly line taper is best for a given style of trout fishing, we need to understand how differences in the line's various sections in its first 35-45 feet impact its performance. Remember, casting a fly line involves creating enough energy on the back cast to keep the line off the water, and enough energy released on the forward cast to allow the fly to land softly on the water.

What impact do the sections of a fly line have?

Running Line:

This is the end of the fly line that attaches to the reel, and is often 50% or more of the line's overall length. If the entire fly line were unspooled, it would be the last section to come out. Because there's usually 40-50 feet of line that's cast out previous to the running line, this section seldom leaves the reel when dry fly fishing.

  • While an essential component, the running line has minimal impact on a line's performance when dry fly fishing at short to mid range distances.

Back Taper Section:

The back taper provides a segment of energy transfer between the running line and the belly of the fly line. Similar to the running line, other than for longer casts, it seldom comes off the reel when dry fly fishing.

  • When false casting with a large amount of fly line in the air, a longer smoother transitioning back taper provides more control.

fly line narrow back taper
  • A short abrupt back taper can make shooting out line on the forward cast easier.

fly line short back taper section

Belly Section:

The belly is the heaviest section of the fly line. The weight of the belly determines how much energy and power it can create. It's the section that makes it possible to cast the line itself instead of relying on the weight of a fly.

  • A long slender belly section allows the rod to load slower and handle more line in the air during false casts.

fly line slender belly section
  • A short stout belly section loads the rod quickly for shorter casts, and increases the amount of line that an angler can shoot out on the forward cast.

fly line taper wide belly section

Front Taper:

The front taper is the transition section between the line's belly and its tip. During the forward cast, this transition helps the energy that was created on the back cast to "escape". This reduction in energy allows the tip section to lay out smoothly on the forward cast instead of violently bouncing back toward the caster. The design of the front taper governs the amount of energy that's passed along to the tip section and eventually the leader and fly.

  • A long gradual front taper causes more energy to escape on the forward cast, which allows for a more delicate presentation. *Note: This style of taper is also referred to as a triangle taper.

  • A shorter abrupt front taper works well for casting in windy conditions and when casting larger dry flies, but tends to land the fly more aggressively on the water.

Tip section:

The very end section of the fly line that the leader is attached to. Some modern fly lines have a loop built into the end of this section to make it easier to secure the leader to. The purpose of the tip is to "release" the remaining power and energy that's been created in the fly line from the cast.

  • The thinner and longer the tip section is, the more energy it will release at the end of the cast, causing a more delicate presentation. However, if the tip is too long and skinny, it will have a hard time turning over larger dry flies.

  • A shorter thicker tip section will maintain more of its energy and allow for more power to turn over larger flies, but often the delicacy of the line landing on the water is compromised.

If your line doesn't have a loop in the tip section, click here to see a cool video on how to connect your line to your leader.

Weight Forward and Double Taper

Fly lines can be broadly categorized into two distinct designs: weight forward and double taper.

Weight forward fly lines:

Weight forward fly lines are constructed with one end of the line larger and heavier than the other (tapered on only one end).

Double Taper Fly Lines:

Double taper fly lines are constructed symmetrically, with each end of the line weighted and tapered identical to the other half.

Weight Forward vs Double Taper for Trout?

Any advantage in performance that a weight forward or a double taper fly line has is nonexistent until at least 35 feet of line is out. This is because the difference between the two does not come into play until the running line is off the reel.

Now I know many people have other opinions about this, but the reality is, since the vast majority of trout are caught at closer than 35 feet away, the differences in how various fly lines perform is rarely based upon whether it's a weight forward or double taper.


How is a fly fishing different from spin casting?

In order to cast any type of fishing line, energy must be created to make the line move. When fly fishing, the energy required to move the line is created by using the weight of the line itself, while in spin fishing it's created by using the weight of the lure. One of the key benefits fly fishing has over spin fishing is the ability to accurately cast lightweight flies. The second major benefit to fly fishing is the ability to make delicate presentations. This is achieved by allowing the energy created on the back cast to dissipate as the line unrolls on the forward cast.

The biggest difference in fly fishing and spin fishing is: Casting in fly fishing involves casting the line instead of casting the fly.

What is a fly line made of?

Fly lines are made up of two components:

The core :

This is the inner portion of the line that provides its strength, as well as it's foundation to which the outer coating is applied to. This is usually made up of hundreds of nylon or dacron strands that are braided together to form a "rope". (Some companies have started using other materials, but the vast majority use nylon or dacron.) Regardless of the material used, the core still serves the same function. The core of the fly line isn't visible unless part of the out coating has been removed.

The coating:

The coating is applied to the core of the fly line to create the outer portion that's visible. The coating is made from various types of PVC, vinyl, polyurethane or other plastics. This portion of the fly line determines the weight, thickness, and taper of the line. In the floating lines used for dry fly fishing, tiny air bubbles are typically incorporated into the coating to assist with floatation.

How are the different sections of the fly line involved in the cast?