Tying a Duncan Loop / Uni-Knot

The Duncan loop, also known as the uni-knot, is one of the most popular loop knots used when fly fishing. The knot is easy to tie and it’s a very reliable knot, retaining about ninety-five percent of the line’s strength when tied properly. By tying your fly to your tippet using a Duncan loop / uni-knot you’ll improve the action of your lure and, as a result, will likely draw the attention of more fish.

The first thing you need to do when tying a Duncan loop / uni-knot is pass the tag end of the tippet through the eye of your hook, as shown in picture A below. Please note, the pictures below do not actually show a tippet being passed through the hook of a fly. Because a tippet and an actual fly would be too small to photograph properly, we used something thicker to represent the tippet and we used a dressed treble to represent the fly.

Once you have placed the tag end of the tippet through the eye of the hook, you will want to create a loop (1 to 1.5 inches in diameter) with the tag end of the tippet, as shown below in picture B.

Now that you have created your loop, take the tag end of the tippet and pass it through and around the loop about four or five times, moving away from the fly as you do so.

Now grab the front of the loop just above the eye of the fly with one hand and grab the tag end with the other. Slowly pull your hands away from each other to tighten the knot. When you have finished tightening the knot, your Duncan loop / uni-knot should look similar to the one in picture D.

After you have tied the knot, simply trim the tag and you are good to go. You have now completed the Duncan loop / uni-knot in its entirety. This knot will prove to be a very valuable tool when using a lure that works best with free movement.