What Size Fishing Line for Trout?

With so many different types and brands of fishing lines, many anglers have trouble choosing the right line for trout. To make things more challenging, trout is one of the most line-shy fish species, and choosing poorly can cost you the catch. 

So, what size fishing line for trout should anglers choose? The size of the trout fishing line depends on the situation, trout species, and fishing method. A 4-pound test monofilament or fluorocarbon line is the best for casting spinners or spoons or still fishing with bait. Use a 10-pound mono or braid when trolling with a 6-to-8-pound fluorocarbon leader. 

Every trout fishing situation is unique, and you’ll need to use different types of lines. Read on to discover which types and sizes of fishing lines are the best for trout. 

Types of Fishing Lines for Trout

Types of Fishing Lines for Trout

There are three types of fishing lines to choose from when fishing for trout. Each of these lines comes with unique advantages and disadvantages.

Monofilament Fishing Line

Monofilament is the most versatile fishing line. Anglers have used monofilament fishing lines to catch trout in every possible way. Mono is cheap, easy to handle, and comes in many different colors and weights.

There are some downsides to using mono, though. Monofilament twists and tangles more than other types of lines, and its high memory makes it difficult to use with heavier-weight lines and light spinners. 

Monofilament lines don’t handle abuse well. When fishing for trout around rocks, check the line frequently for nicks. Remove abraded sections of the line to prevent losing the tackle and the fish.

Fluorocarbon Fishing Line 

When submerged in the water, the fluorocarbon fishing line is nearly invisible. Trout is one of the most line-shy fish species, and using an invisible line for trout gives you a huge advantage.  

Besides being hard to see underwater, fluorocarbon has low memory and withstands abrasion and UV damage better than monofilament. Fluorocarbon is also more sensitive than monofilament because it has less stretch.

Fluorocarbon is a great line, but it’s not without drawbacks. Fluorocarbon is a dense line and sinks faster than mono, so it isn’t the best choice for float fishing. Fluoro is also much more expensive than monofilament fishing lines. 

Most anglers fishing for trout use fluorocarbon as a leader on monofilament or braided fishing lines when casting heavier jigs or trolling.

Braided Fishing Line

Braided fishing line is popular among bass and walleye anglers because of its strength and sensitivity. A braided line doesn’t stretch, allowing the anglers to feel every bump, nip, or strike on the line. 

This trait comes in handy when fishing for a lake trout in deep waters, where using a monofilament line would make it impossible to detect a bite. 

Although extremely strong, the braided line has a thin diameter which is ideal for most trolling applications. Use small divers to get a braided line deep in lake waters. 

The biggest downside of a braided fishing line is its visibility. A braided fishing line is useless if you are mostly fish clear, small streams and rivers. In clear waters, braided fishing line is highly visible, deterring line-shy trout from biting your bait. 

Different Fishing Line Sizes for Trout

The right pound test line for trout will depend on the body of water you’re fishing in and the size of the trout you’re trying to catch. The type of fishing line you choose will depend on whether you’re fishing for river or lake trout. 

Fishing for Trout with Monofilament Line

When using a monofilament line for trout, choose a 2-to-4-pound test for spinner fishing or still fishing in clear streams. Depending on the size and species of targeted trout, use a 6-to-8-pound test monofilament line when trolling with small gang trolls or light tackle.

Fishing for Trout with Fluorocarbon Line

If you decide to fish for trout using a fluorocarbon fishing line, choose a 4-to-6-pound test line for light tackle and fishing in clear streams and lakes. When targeting larger fish, switch to heavier braided or monofilament lines and use fluorocarbon as a leader to maintain invisibility. 

Fishing for Trout with Braided Line

While a braided fishing line might not be your first choice when fishing for trout, if you decide to use it, choose a 10-pound test braided line. A braided line casts light lures smoother than a monofilament line, but it’s highly visible. 

When fishing for trout with a braided line, use monofilament or fluorocarbon as a leader.

What Is the Best Fishing Line Choice for Trout?

The species of trout you want to target is one of the first things you need to consider when looking for the best fishing line for trout. The line that works for a huge brown trout will be much different from a line used to catch a speckled trout. 

No type of fishing line is ideal for all species of trout in all situations. But, a 4-to-6-pound monofilament or fluorocarbon fishing line works most of the time. 

These types of lines are strong enough to troll with light trolling rigs but light enough to cast small lures smoothly. Both monofilament and fluorocarbon lines work for still fishing, and you can use monofilament as a leader if fluorocarbon sinks the bait. 

If you’re targeting trophy trout, scale up to an 8-to-10-pound test braided line in combination with monofilament or fluorocarbon leader. 


Picking the right size fishing line for trout isn’t easy. What size fishing line is best for trout depends on several factors, including trout species, the body of water you’re fishing in, and the situation. 

If you’d have to choose a single-line setup that works in most scenarios, it would be a 4-to-6-pound test monofilament or fluorocarbon line. Either of these lines is a good option for most trout fishing situations. 

Choose a 10-pound test braided fishing line, when fishing for large trout species. To avoid spooking trout with a highly visible braided line, use fluorocarbon or monofilament as leaders.