September 22, 2021

Author Image

Team Guidesly

Intermediate Fly Line: When to Use

Intermediate Fly Line: When to Use

Intermediate fly lines are considered a jack-of-all-trades for many fly fishermen. They can be used in a wide variety of conditions and is often the go-to line for those that have to only choose one. 

Whether fishing from the boat or the shore, let's find out when to use intermediate fly lines. Let's talk about what it is.

The Basics of Intermediates

The intermediate fly line allows anglers to fish in the upper, shallower portion of the water column. Typically, it is used for a few feet below the surface because it sinks at a slow rate and can help you target fish as they swim at varying depths. 

Now, there are no specific standards set for the sinking rate of an intermediate fly line. They generally have a 1 inch per second (IPS) sink rate although some lines are at 1.25 IPS while others can reach 2 IPS. It’s best to ask the manufacturer of the line that you’re interested in on the specific details. 

There are two main kinds of intermediate fly lines – monofilament and braided. They are often transparent and while they may have their own specific uses, they both perform better if dipped in water beforehand. 

The mono lines are more translucent once it's in the water and can take on a slimy appearance once they’re wet. This has earned it the moniker of a slime line or glass line. However, monofilament intermediates are prone to line memory and need to be stretched periodically. 

Braided intermediate lines, on the other hand, are softer, less transparent, and are less prone to line memory. They can come in semi-transparent variants and even camouflage designs to make them less visible to fish. They are also more sensitive to detecting bites. 

While intermediate fly lines can reach the bottom if you retrieve them slowly, it's generally best to only let them sink into the top few feet of water. This is where calculating the sink rate is essential. For example, an intermediate fly line with a sink rate of 1 IPS will sink 10 inches in 10 seconds. If it has a 2 IPS on the other hand, it will sink 20 inches in 10 seconds, and so forth.