How Strong Should Your Leader Line Be Compared To Your Main Line


I’ve seen many new and experienced anglers ask the question, “How strong should a leader line be compared to your main fishing line?” It seems like a simple question, but it comes with a not so simple response.

The problem with this question is that there are so many variables to consider, making it difficult to provide a solution that fits all situations. That being said, I personally use a general rule of thumb when I’m not sure what to do.

When deciding what strength of line I should use as a leader line, a personal rule of thumb is 5 lb (~2.2 kg) or the next common line pound test above or below my mainline. Go with a stronger leader line if you’re concerned with abrasion. Go with a weaker leader line if you’re concerned with line visibility and castability. Either the mainline or leader line strength should exceed the rod’s rated strength.

Selecting the right strength for your leader is a trail-by-error process. Meaning that you try one type of line, and if it breaks or doesn’t like its performance, you adjust with using a different line later.

Depending on the fish species you’re fishing for, the environment (the sandy or rocky floor, the current or waves, surrounding vegetation, debris), and your fishing style and personal preference makes it difficult for anyone to tell you exactly what you should do.

If you’re not entirely sure what the purpose is of a leader line at this point then check out my blog post.

But I hope to provide you with the information you need to give you a good starting point on what things to consider when determining what strength leader you should use.

My leader line recommendations that I personally use:

When To Use A Leader Line Stronger Than Your Mainline?

Most anglers tend to use a stronger leader than the mainline to prevent the line from being cut through.

There are a bunch of different factors that can contribute to your line being cut off, such as:

  • Fishing rubbing against a fish’s sharp teeth or body
  • Rocks with sharp edges
  • Barnacles on rocks
  • Random debris underwater

If you’re fishing in an area with heavy current or waves then it can make things worst.

How Does A Stronger Leader Prevent The Line From Being Cut Off

We use a stronger leader in these situations has nothing to do with the actual strength of the line. But it has everything to do with the thickness of the line.

The stronger the line, the thicker the line. This extra thickness provides more “meat” that a fish, rock, barnacles, etc., have to cut through for the line to snap.

This sounds pretty logical and makes a lot of sense, but there are some downsides to having a stronger leader line that you need to be aware of

The Downsides With Having A Stronger Leader Line Than Your Mainline?

At this point, you might be thinking about what are the potential downsides of using a stronger leader? Unfortunately, there can be a few downsides, and some of them are not so obvious until you’re faced with the issue.

So I will try to break down the different possible downsides with using a stronger leader.

Change in Performance: Depending on the type of leader and how thick your leader line is could change how your bait behaves underwater.

Generally speaking, the thicker lines will have more of a tendency to float than sink.

More Visible Underwater: The thicker lines are more visible underwater, giving an unnatural presentation to any fish that might notice.

How much of an effect this will have will depend on the fish your fishing for. From personal experience, if your fishing for fish that are ambush and territory, then this would not have much effect because they tend to attack anything that moves.

Getting Snagged To Early: If you’re using a stronger leader line because of the rocks in the area, then you have to consider the possibility that you could also get snagged on a rock.

If you get snagged on a rock with a leader line that is stronger than your mainline, then what do you do? If you try to pull on the line to break it, what will you lose?

The chances are the line will probably break at the mainline-to-leader knot. That being said, there is a real possibility that your line might break somewhere along the mainline, especially if you did a solid knot.

If this happens enough times and depending on how much line you lose, it can be a quick way to ruin a fishing trip if you lose too much of your main fishing line to prevent you from fishing the way you want to.

When To Use A Leader Line Weaker Than Your Mainline?

Most anglers tend to use a weaker leader than the mainline to improve their bait presentation and protect their fishing rod and mainline from damage.

Reduced Visibility: A weaker leader line also means the line is thinner as well. This helps with reducing the leader’s visibility as a fish approaches your bait. Reduced line visibility minimizes the chances of a fish being spooked off, which will help with your catch rate.

Change in Performance: A thinner leader will move in the water differently than a thicker leader made of the same material. A thinner line will have less of a tendency to float than the thicker lines. Also, thinner lines are generally more flexible, allowing them to move in the water more naturally.

Protecting Your Fishing Gear & Mainline: Many anglers use a leader line to protect their mainline from snapping or rod from breaking. Let’s say you got snagged on a rock and your leader line is weaker than your mainline. If your line were to break on your trying to get un-snagged, then you would at least know what your line will break at the leader and only use a lure rather than the line breaking at some point along the mainline. If you’re fighting a large fish and have your drag set too high, your leader will break first rather than your rod.

The Downsides With Having A Weaker Leader Line Than Your Mainline?

If you’re wondering, “a weaker leader line means that it’s thinner, then that would mean it’s easier for sharp rocks and teeth to cut through the line, right?”. And you would be absolutely correct with that conclusion.

A thinner leader line is more susceptible to abrasion, and it’s easier for things like sharp teeth, rocks, barnacles, etc., to cut through the line. But there are things you can do while fishing to minimize the chances of that happening.

Inspect your leader line: By inspecting your leader line before every few casts to feel how rough and rocky the terrain is. You inspect the leader line simply by running your fingers along the leader line. A new line that was never used is going to feel super smooth. If your line is being damaged, it will have spots where it will feel a little rough.

That roughness you feel is actually little micro cuts into the line. Depending on how rough the line feels and how long it took to get to that point will determine when you should replace your leader line with a new one.

What Type Of Leader Line Should You Use?

There are generally two types of fishing line material that make for good leader lines:

  1. Monofilamnet
  2. Flourocarbon

These materials have their own advantages and disadvantages, which should be considered when deciding if you should use a stronger or weaker leader.

AdvantagesDisadvantages
Monofilament Leaders– Good Strength
– Tendency to float
– Cheapest option On The Market
– Provides good knot strength
– Tendency to float
– Poor abrasion resistance
– Stretches (Shock Absorbing)
– Visible underwater
– Becomes weaker as it absorbs water
Fluorocarbon Leaders– Good Strength
– Very low visibility
– Tendency to sink
– Excellent abrasion resistance
– Good knot strength
– Has the same properties dry or wet
– Tendency to sink
– Stiffer than Monofilament
– Costs more than Monofilament

My Personal Preference Regarding Leader Lines

Generally, I like using weaker leader lines more to protect my mainline and equipment. Having a fishing break is a great way to ruin the day on something silly like getting snagged. Though there are ways you get unsnagged without putting your rod at risk of breaking, it is for another time.

Also, having your mainline snap on your is no fun, especially if you lose enough line where it can impede or, in some cases, stops you from fishing, is just equally as no fun.

I like the cost-effectiveness with monofilament, but since I do like fishing for codfish that love to hide in rocky terrains, I can use a fluorocarbon line designed to withstand heavy abrasion without having to increase the strength.

Fluorocarbon gives me the best of both worlds when it comes to fishing in heavy rocks.

Personally, I like using the Berkley Trilene Fluorocarbon Leader Line. It has served me well for the years. But if you want to start with something a bit more budget-friendly, then go with the Berkley Trilene Big Game Monofilament Fishing Leader Line.

Happy Fishing and Tight Lines!

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