Sinking Lines - The Basics

Want to watch the video breakdown? Here it is below. 



Fly lines can be confusing. Especially sinking fly lines. This blog  breaks down the most used styles in common, but technical lingo and should give you a better understanding of the different sinking fly lines.

Sinking lines can be incredibly helpful, and, in some instances, necessary, if you actually want to catch fish. From lakes to smaller streams you will need to vary what sinking line you choose - or try and find a fly line that covers MOST of your needs.

The three basic types of fly line discussed are:

- Intermediate

- Full Sink

- Sink Tip

In a perfect world, you could fish a floating line all day and never need to get a fly down deep. Top water eats are what many anglers live for, but sadly, they are not the norm for the vast majority of our fisheries!

An intermediate line sinks at about 1.25 f.p.s. (feet per second). This fly line is designed for getting and keeping your fly in the 1-4’ range. This is a sinking line for low and slow water or when gamefish are pushing baitfish up and busting on or near the surface.

We use these lines in VA for 2 reasons typically: 1) when water flows get low, and 2) when baitfish are being pushed up from the depths. There are two specific instances in my mind - when our summer flows drop and we start fishing weightless baitfish patterns. The intermediate line helps the flies get down some in the water, but not deep enough where you’re hanging up every cast. When fishing for striper or other gamefish in our lakes, there are times when the gamefish drive shad up to the surface to eat them. When this is happening, fishing a intermediate can be very effective.

An intermediate fly line is popular for saltwater anglers as it gets the fly below the chop in the water, but not crazy deep. As well, it helps you present the fly at a distance without the line eventually sinking into the mud and making your Clouser Minnow drag across the bottom of the sand and grab every piece of grass and rock down there (though on some occasions that can attract fish). I primarily use an intermediate saltwater line when surfcasting to bluefish and spanish mackerel on the NC coast.

On the opposite end of the spectrum from an intermediate line, you have a full sinking line. This is a fly line that’s primary purpose is dropping to the depths and keeping your fly there. These lines are very effective, and are the common line of choice on larger and faster moving watersheds as you can get your streamer into the zone and keep it there. This may be lakes or rivers (especially larger rivers).

Full sink lines have more variation within them than the other two styles, as there are MANY different ways manufacturers make them today. There are typically two varying styles that both revolve around sink rate.

  1. Varying Sink Rate
    - These fly lines offer varying sink rates within the same fly line. This means your fly line will typically drop at an angle. Typical sink rates would be the ever popular: 3/5/7 or I/3/5. These numbers signify the varying sink per second rate.

    From these numbers you would know the 3/5/7 sinks at a rate of 7 inches per second at the head, 5 inches per second in the middle of the head and 3 inches per second at the back of the head. 1/3/5 means the fly line will sink at a rate of 5 inches at the tip, 3 inches in the middle, and 1.25 (an intermediate rate) at the rear.
  • These lines cast better than the old school lines as they are typically tapered like a traditional fly line.
  • These lines sink at an angle in water so you typically have a better feel for what the fly is doing compared to what I term the “level sink rate” lines. 
  • I really like these lines in lakes.


  1. Level Sink Rate
  • These fly lines sink at the same rate throughout the head of the line and are typically branded by Scientific Anglers as SINK 25 or SINK 30. The number in this line doesn’t refer to the sink rate per second, but rather the distance of sinking line. These can be purchased in varying depth rates, from what I’ve found (and sell in the shop) they vary from 4 to 8 i.p.s. (inches per second).
  • These lines shine in larger rivers where you want to get down fast and stay in that zone, whichever depth that is.
  • These lines typically don’t cast as accurately as other kinds of sinking lines.
  • I tend to fish these lines in rivers more as they get down fast and stay in the same depth the majority of the time you retrieve it.

Depending on the sinking line you get you can get depths on the extreme side of 30’ by stripping out a bunch of line casting as far as you can and counting down to your desired depth. This technique would primarily be used on lakes and on a still day. On average these lines are most effective from 3-15ft. The depth all revolves around which line you pick, and unfortunately there is not one line that is perfect for every situation and depth.

Sink tip lines are a hybrid line. They typically have a floating running line and a portion of the head is floating, but the tip of the line sinks. On medium/smaller rivers these lines are superior to full-sink lines because of the control they give you.

As with the full-sink line there are many variations of sink tip lines. You can get some that have a 10’ head - you can get some that have a short 3’ head. And the level of sink is all over the place. Type 6 being the one I use most commonly on our local VA rivers. 

In faster moving water or large structure off the banks, you’re able to mend the floating running line/partial head to keep the fly in the zone. You can also cause the fly to act erratic by bring a down stream mend and making the fly appear to dart downstream off the bank as baitfish typically do to evade predators.

With a sink tip line you’re able to cast behind logs and structure that runs parallel to the bank and make it dart out of the structure by doing a curve cast. These are techniques you can’t use with traditional sinking lines (or even conventional setups.)

Due to the nature of the sink tip line they do not get as deep as a full-sink line (obviously). So I would primarily suggest them on smaller/medium sized rivers. Depths would be realistically 10’ max. The average depth of the rivers I use them on is probably 4-8’ deep for a type 6 line (which sinks at app. 6” per second”.

This is my preferred sinking line style in the majority of my freshwater river fishing. I use them for everything from trout to smallmouth to striper when they’re pushing up the rivers.

Gone are the days of "chuck n duck" fishing. Modern sinking lines are designed to cast as similar to a floating line as possible (though I see this only getting better). You can find a sinking line that perfectly fits your fishing style and the river or lake you frequent.  It may take a little bit of practice casting them, but with time you'll be sending flies to the depths and taking photos with monstrous fish.