Double Uni Knot

The Double Uni Knot (also known as the Double Grinner Knot) is one of the most popular and dependable line-to-line connections in all of fishing. It works by tying two individual Uni Knots back-to-back, one on each line, then cinching them together into a single compact join. Because each knot grips independently, it handles differences in line diameter and material far better than many other line-to-line knots, making it the everyday choice for connecting braided mainline to fluorocarbon or monofilament leaders.

How to Tie the Double Uni Knot

1. Overlap the two lines by about 8 to 10 inches so the tag ends face opposite directions.
2. Form a loop with the first tag end back along its own standing line, then make 3 to 4 wraps through the loop around both lines. Pull the tag end to snug the first Uni Knot.
3. Repeat with the second tag end, forming a loop back along its own standing line and making 3 to 4 wraps through the loop around both lines. Snug this second Uni Knot.
4. Moisten both knots thoroughly with saliva or water.
5. Pull the two standing lines in opposite directions to slide the knots together until they seat firmly against each other.
6. Trim both tag ends close to the knot body.

When to Use This Knot

The Double Uni Knot is your all-around line-to-line connection. It handles mixed materials gracefully and is easy to learn, so it works in almost every scenario where two lines need joining.

• Connecting braided mainline to a fluorocarbon or monofilament leader
• Joining two monofilament or fluorocarbon sections of different diameters
• Quick leader attachments for spinning, baitcasting, or surf setups
• Any situation where you need a reliable splice and don’t want to master a complex knot

Pro Tips

• Use 3 to 4 wraps for monofilament and fluorocarbon, but increase to 7 or 8 wraps on the braided-line side so the braid grips properly.
• Always moisten before cinching — dry braid especially generates friction heat that weakens the connection.
• After the knots slide together, give a firm pull on each tag end individually to make sure neither side slips before trimming.
• If you already know how to tie a standard Uni Knot, you already know this knot — it’s simply two of them tied facing each other.

Pros and Cons

Pros:

• Very easy to learn, especially if you already tie the Uni Knot
• Handles different line types and diameters well in a single connection
• Works reliably with braid, monofilament, and fluorocarbon
• Symmetrical design that cinches evenly under load

Cons:

• Bulkier than slimmer alternatives like the FG Knot, which can catch in rod guides
• Slightly lower strength rating than advanced knots such as the FG or Alberto
• Requires extra wraps on the braid side, which can be easy to forget
• Not the best choice for very heavy offshore leaders where maximum strength is critical