Fly Fishing Line

What a fly line does

A fly is almost weightless. A spinning lure carries its own mass, but a fly needs something heavy to pull it through the air, and that is the fly line. When you cast, the rod loads against the weight of the line, and the line carries the leader, tippet and fly out with it. So the line is the part of your outfit that does the casting, and it is worth getting right.

The table above lists the fly lines we track on Amazon US, one row per line model, with the weights each is sold in. Behind the line on your reel sits backing, and in front of it sits a leader. Lines come in several tapers, densities and weights, and the choice is mostly mechanical: match the number to the rod, then pick the taper and the sink rate for the fishing.

The weight number

Fly lines are numbered from 1 up to 15, with 1 the lightest. The number follows a standard, which Wikipedia dates to 1960 and credits to AFFTA, and it is based on the weight of the first 30 feet of the line, in grains, not counting any level tip. A 5-weight line, for example, has a target of 140 grains with a range of 134 to 146. The point is simple: a heavier number means a heavier line, and a rod is built to cast a given weight.

Two cautions. First, the standard measures only the first 30 feet, so it does not tell you how the rest of the line behaves. A writer on the Sexyloops site, which discusses line ratings, makes the point that anything beyond 30 feet adds weight and that the rating therefore does not describe the total head weight. Second, some lines run heavier than their label. The same writer says many lines run a full rating or more over, and credits one maker for being open about it. So a 5-weight label does not always guarantee a good match with a 5-weight rod. If a rod feels sluggish with a line, the line may be heavy for its label.

In the table, the Line weight column shows a small gauge, a ruler from 1 to 12. The number shown comes from the Amazon listing for the variant we track, and the mark under it says so. Many lines are sold in a range of weights, and where the maker states the range, it is in the More specs toggle. For the matching rod, our fly line weight chart guide lists the common pairings, and the pages for 3-weight, 5-weight and 8-weight rods list the rods built for each number.

How to read the code on the box

Most makers print a code. WF5F reads like a licence plate, and once you can decode it you can decode most of the table.

• The first letters are the taper. WF is weight forward, DT is double taper, L is level, and ST or SH is a shooting taper or shooting head.
• The number is the line weight.
• The last letter is the density. F is floating, S is sinking and I is intermediate, which sinks slowly.

So WF5F is a weight-forward 5-weight floating line, and DT3F is a double-taper 3-weight floater. Wikipedia gives the example WF-5-F in the same way. The pattern is a convention, and not every maker follows it. Sinking and sink-tip lines in particular are sometimes labeled by grain weight or by a maker's own sink-rate system. For the code on a given product, use the maker's page.

Taper: weight forward, double taper and the rest

Weight forward lines put the bulk of the weight toward the front and then thin to a running line. That makes them easier to cast at a distance and to shoot line. Of the lines in the table where the taper is stated, most are weight forward.

Double taper lines are symmetrical, with a level belly and a taper at each end. Some anglers like them for short, delicate presentations, and and some anglers like that you can reverse the line on the reel when one end wears. In our table, the Cortland 333 Double Taper DT5F, the Cortland 444 Peach DT3F, the RIO Mainstream Trout DT 4 and the Aventik Sure Cast Double Taper are examples.

Level and running lines appear on the floating lines page. A level line has the same diameter along its length, and a running line is the thin section behind the head, sold separately by some makers.

Specialty tapers have their own names, such as Airflo's Tactical Taper, Power Taper and Universal Taper, Royal Wulff's Triangle Taper, and Cortland's Big Shot. They are the maker's description of how the weight is spread, and the best way to compare them is to read the maker's page. Our guide to types of fly line covers the main families, and the Skagit vs Scandi guide covers the two-handed styles.

Floating, sinking, intermediate and sink tip

Floating lines float along their entire length. Wikipedia explains that air bubbles are embedded in the plastic coating. They are the default for dry flies and for nymphing, and most of the lines in our table are floating. 136 of the 190 are lines their maker calls full floating, and they have their own page.

Sinking lines have heavy particles, such as tungsten, in the coating, and they are rated by how fast they sink, in inches per second. In the table, the SF WF4S Full Sinking lists 3 inches per second, per its Amazon listing. Wikipedia notes that there is no industry-wide standard for sink-rate types, so ratings vary by maker.

Intermediate lines sink slowly. The Aventik Intermediate WF lists 1.5 inches per second in its listing.

Sink-tip lines have a floating body and a sinking tip. The Aventik Sinking Tip / Diving Head lists 5 to 6 inches per second, and the Moonlit Floating Intermediate Sink Tip S1 lists 1.5 to 2.5. These are the numbers each maker or seller gives, and they are not comparable across brands without checking how each one was measured.

Core, length and loops

Core is what is inside the plastic coating. The table includes braided nylon multifilament, braided and PVC-coated braided cores, a monofilament core on the Cortland Hi-Vis Flip, and braided cores described by strength, such as Airflo's "Braid, 15 lb." I would not choose a line on core alone, since the coating and taper matter as much.

Length runs from 80 feet on the Cortland Headwater to 120 feet on the Airflo Ridge 2.0 Super Trout in our data, with 85, 90 and 100 feet common. The length matters for how much room you leave for backing. Our guide on how much backing to put on a fly reel shows how to work it out, and the fly reel size guide helps you match line and reel.

Welded loops are factory-made loops at the end of the line that make attaching leader and backing easier. In the More specs toggle you will see front, both ends or none where the maker or listing states it.

What the marks under the values mean

• maker means stated on the manufacturer's own page.
• claimed means a manufacturer's claim with no independent lab or standard named.
• listing means taken from the Amazon listing and not confirmed by the maker.
• — means we could not confirm it, and we do not guess.

In the fly line table, line weight is usually a listing mark, because the Amazon listing is where the variant's weight appears. Taper, density and length are often from the maker. The Hook Drawer in my imagination holds three half-used spools of line from reels that no longer exist, each labeled in marker with a weight nobody can verify. A table with marks is the opposite of that drawer.

How to choose

Start with the rod. Match the line to the weight printed on the rod. If your rod is a 5-weight, start with a 5-weight line. Our rod pages list the weights makers state, and 5-weight rods are a common start. If you are fishing for trout, our guide on what weight fly rod for trout goes into the matching.

Then the density. A floating line is the usual first line, because it handles dry flies, nymphs under an indicator and many streamers. Add a sink-tip or sinking line when you need to fish deeper or in current.

Then the taper. Weight forward for most, double taper if you like short, delicate casts and want the option to reverse it. For two-handed rods, check the maker's recommendations.

Mind the water temperature. Our data records one on only a few lines, such as the Royal Wulff Triangle Taper lines, listed as cold. If a line has no stated temperature range, the maker's page is the place to look.

Mind the budget. The table spans our lowest price tier up to the middle of the range. A lower-tier line casts and floats like a line, and a more expensive one usually offers a specific taper or a stated coating. Check price on Amazon for the current figure.

For specialist jobs, there are narrower lines. Euro nymph setups, for example, use their own lines, and our table includes the Airflo Superflo Max Euro Nymph and the Aventik Euro Nymphing Floating Level Line.

Common mistakes

The classic error is reading WF5F as a model name and buying three of them in different colors. Another is simpler: buying a line without checking the rod's rated weight. Another is overloading the reel and leaving no room for backing, or the reverse, buying so much backing that the line sits too low on the spool. A third is ignoring the leader. A line that is a good match with a mismatched leader still casts badly.

And one more: taking marketing words as specs. "Ultra-low stretch" and "memory-free" describe a feel that the maker has in mind. If a listing offers no number, the words are the maker's opinion.

Care in brief

Wipe or wash the line, let it dry, store it out of the sun and away from solvents. Our guides on how to clean fly line and how long fly line lasts cover the details. For spooling the line onto a reel, see how to spool a fly reel.

Brands in the table

The table includes lines from Airflo, Aventik, Cortland, Maxcatch, Moonlit Fly Fishing, RIO, Royal Wulff, Scientific Anglers and Snowbee, among others. Royal Wulff has a particularly large set of Triangle Taper variants. Not every brand has a page of its own, and the brand catalog lists the ones that do. If you use a line from another source with a reel, the fly reel pages show which line weights each reel lists.

Where to go next

If you want only floating lines, go to the floating fly lines page. If you are filling a reel, the backing page covers what goes under the line. And if you are still choosing a rod, start with the fly rods page.