Obsessed with Perfection. Crafted for Excellence.

At Opsin, our passion for fishing drives us to achieve perfection. Starting in Japan, the birthplace of precision, our fluorocarbon lines are meticulously crafted through a slow extrusion process. This results in low diameter, supple, and stealthy lines, perfect for the discerning angler. Ideal for targeting line-shy fish in clear water conditions.

Let customers speak for us

from 74 reviews
Quality line at a price I like

We have been using Opsin for about three years now, and we have never looked back. I love the fact that they offer flourocarbon as small as 6 and 10 pound all the way up to triple digits. We have yet to have any of our lines fail. Honest to God!

Ryan candelaria
"The Deckhander" Five Opsin Spools at the 50+ yard capacity
Fluorocarbon and sweater

Owner responded to my order within 5 minutes of purchase. Couldn't ask for anything better.

Jason Mcclanahan
Fluorocarbon Leader Line 80 lb .77mm
Exceptional product

I used the 20lb Opsin Fluorocarbon earlier this summer to catch back to back White Seabass 16lb and 18lb at the Coronado islands. These were my first White Seabass in 20 years.

George "Robbie" Robinson
20 lb .37mm, 100yd
Fantastic Product

The 40lb fluorocarbon line worked well on bluefin and surface iron yellowtail fishing. I am now using this line for deep water yoyo yellowtail, lingcod and other rockfish. I also use, 15lb thru 130lb Opsin Fluorocarbon fishing line.

George "Robbie" Robinson
40lb .55mm
25 lb. Leader for yellow tail

Fish Opsin for yellowtail, amazing product never change the leader coughs 5 yellows on the same 25 lb leader

Alan Jaimez
35 lb, .50mm
Thin and strong

I just started using this line I like it I fish a lot on crowded boats my line is constantly rubbing against either the boat or someone else’s line although I check my leader often this line just doesn’t seem to fray up as much

Deon Calamia
Fluorocarbon Leader Line 60lb .73mm
Awesome thin line

I tie my jigs directly to the flouro.I lend my gear a lot as I charter and bring my friends!My past trip we caught almost limits the biggest was 99.4 dresses we lost one fish to breakage but that was an angler error

Deon Calamia
Fluorocarbon Leader Line 100 lb .97mm

I used Monofilament and was Skunked. Next Trip, with Opsin Fluorocarbon, I caught the first Fish, with 33 other Fisherpeople.

John
30lb, .44mm

Love it!! Best line I’ve ever used

J.l.
"The Deckhander" Five Opsin Spools at the 50+ yard capacity

Very good product. Have now used 15,20,25,30,35,40,&50 with success. Have 60 too but unused. All have superior knot strength and smaller line diameter than competitors. Got 5 bluefin and 6 yellowfin on my most recent trip using opsin!

n.n.
40lb .55mm

Super stoked on this package! Already caught 30-40 pound yellow tail!

Pablo
"The Deckhander" Five Opsin Spools at the 50+ yard capacity

OPSIN ROCKS!!! Started using it last season and now that’s all we use!!! PERFECT FOR BLUEFIN, YELLOWFIN, YELLOWTAIL, and DORADOS!! We LANDED a 100lb BlueFin on 35lb Fluro on our Light Outfit:
ROD: Seeker Black Steel 15 - 20lb 8FT
REEL: Diawa Lexa 400 TW
BRAID: 40lb
Thanks Greg!!!

rich
"The Deckhander" Five Opsin Spools at the 50+ yard capacity

This line made the difference on a tough fly line note for 30-40 lb BFT. I didn’t break any off and landed 10 and passed another 3 off. Great line. Much more flexible and than the seaguar blue and much stronger than gold

William
30lb, .44mm

This line really made the difference on my last 3 day trip out of San Diego. I was the hot rod landing 12 Blue fin to 40 pounds and 4 yellow tail to 25

William
30lb, .44mm
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Opsin Fluorocarbon Fishing Line – 4 lb (0.16 mm) 100 YD
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Opsin Fluorocarbon Fishing Line – 20 lb (0.37 mm)
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Opsin Fluorocarbon Fishing Line – 25 lb (0.40 mm), 25 YD
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Opsin Fluorocarbon Fishing Line – 30 lb (0.44 mm), 25 YD
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Opsin Fluorocarbon Fishing Line – 35 lb (0.50 mm), 25 YD
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Opsin Fluorocarbon Fishing Line – 40 lb (0.55 mm), 25 YD
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Opsin Fluorocarbon Fishing Line – 50 lb (0.59 mm), 25 YD
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Opsin Fluorocarbon Fishing Line – 60 lb (0.73 mm) 25 YD
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Opsin Fluorocarbon Fishing Line – 80 lb (0.83 mm) 25 YD
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Choosing Your Fluorocarbon: Line Weight & Species Guide

Select line class based on your target species and technique. For tuna under 50 lb, opt for 20–40 lb line; yellowtail and dorado may need 30–60 lb; big bluefin or swordfish call for 80–200 lb leaders. Match leader length and diameter to water clarity and rig type: clear water demands slimmer diameters, while rocky structure warrants thicker, abrasion‑resistant line. Still not sure? Check our species guides and comparison charts on product pages.