There are many different tools that help out fly fisherman to solve the riddle of casting flies at fish. There is nothing more integral to the pursuit of fish with a fly than your fly rod and fly line. Without the right rod and line for the task, you may find yourself struggling to present your flies successfully to feeding fish. Just like a golfer has many different clubs at their disposal, each one for a specific situation, a fly fisherman has many different fly lines at their disposal for a myriad of different fishing situations.

Different WT Lines

Each fly line, regardless of its intended use, has a designated line WT.

• For optimum compatibility, match your fly line WT with the WT rating of the rod with which you intend to use the fly line. This ensures that the power of your casting stroke and rod will deliver the fly line with ease.

Double Taper (DT) and Weight Forward (WF) Lines

The classic, all-purpose fly line.

• Double taper lines are typically a bit thinner, and are good for dry-fly fishing as they are more supple and fine. Double taper lines are great because you can switch the fly line around and extend the use of the line longer than others. DT lines are becoming harder and harder to find these days.
• Weight Forward lines are the most common fly lines in use. When matched with your fly rod WT, you can cast and fish nymphs, indicator nymphing set-ups, dry flies, dry/dropper combos, and a wide range of streamers. If you prefer to fish a specific way most of the time (nymph all the time or a dedicated streamer fisherman), you may want to try out lines that are specifically made for that purpose. But if you want to do it all, then a WF line is going to be your best bet.

Nymphing Lines

If you enjoy primarily nymphing to catch fish, then using a nymphing-specific line may aid you in fishing more effectively.

• Most nymphing specific fly lines have brightly colored tip sections that help in detecting sub-surface strikes. This is hugely beneficial for any nymph fisherman, and most other lines do not have these characteristics.
• The tip of the fly lines typically has a larger and more abrupt taper than a WF or DT line. This helps turn over long and heavy nymphing leader set ups and indicator rigs with more ease than other lines.
• The mid sections of the line are usually smaller and more supple, making the in-hand feel more direct and making it easier to feel strikes in the line as you hold it with your off hand.

Sinking Lines

If you want to truly fish down deep in lakes, salt water, or the deepest darkest holes of the river with wet flies, nymphs, and streamers, a sinking line is a must have in your arsenal.

• Sinking lines do exactly what they say, they sink. If you need to ply the bottom of a lake or pond because none of the fish are up on the surface, you need a sinking line to do so. Casting a long leader, a weighted fly and even some split shot with a regular floating fly line, and then waiting for it to sink to the bottom and slowly creeping it back isn't the most successful and easiest way to fish. Your casts will be messy and hard, and you won't be keeping your flies on the bottom the whole time. Go with a full sinking line and you'll see a major difference.
• A must have for any salt water angler. For getting below the heavy surf and surface currents, you'll need a sinking line to cut through it all and get down into the water column. Floating lines are easily pulled around in the surf and it makes it harder to get the fly down to where the fish are.

Streamer Fly Lines

For dedicated streamer fisherman, ditch the same old WF fly line and go for a sinking tip, streamer specific line.

• Casting big streamers is tough. These streamer fly lines have larger and more dynamic tapers that make it easier to cast large streamers and deliver them more effortlessly.
• Thicker mid and tip sections means that you can pick up the line off the water quicker, and shoot more line with less false casting involved, a huge benefit to fishing a big streamer all day.
• The sink tip sections are really helpful in getting the streamer right down deep where it should be, quicker and with less time needed to wait for the fly to sink.
• If you want to get into a very specific form of fly fishing, it's a great idea to use a fly line that's designed specifically for that purpose; a streamer line for streamer fishing, a nymphing line for nymph fishing. If you want to do it all, then the classic WF line is your best bet. Purchase a few spare spools for your reel, and spool up a few types of line and keep them in your gear bag. Switching your line to a full sink only takes a few seconds, and it may mean you can reach the fish better than trying to pepper a long leader with split shot in order to get it down deep.

Every tool has a specific use, and any craftsman knows just the right tool to get the job done. Fly fishing is no different!