Tackle Index
Knot

Double Uni Knot

Line to line of similar or slightly different diameter, main line to leader.

Last reviewed 26 September 2026 · Editorial policy

At a glance

What this knot is for

Joins
Line to line of similar or slightly different diameter, main line to leader
Line types
Any combination of mono, fluorocarbon and braid, provided the diameters are not too far apart.

Reach for it when

  • Joining braid main line to a mono or fluorocarbon leader
  • Joining two lengths of mono, e.g. repairing line or building a shock leader
Method

How to tie the double uni knot

  1. 1Overlap the two lines to be joined by 20–25cm.
  2. 2Using one line's tag end, tie a uni knot around both strands: form a loop over both lines, then wrap the tag end through the loop and around both lines 5 times for mono or 7–8 for braid.
  3. 3Snug this first uni knot down onto itself, but not fully tight yet.
  4. 4Repeat the process with the other line's tag end, wrapping it around both strands in the same way to form the second uni knot.
  5. 5Moisten both knots and pull the two standing lines apart slowly so the two knots slide together and lock against each other.
  6. 6Trim both tag ends close to the knot.
Double Uni KnotDiagram: Tackle Index

Work on a flat surface with enough line in your hand to pull the knot down firmly, and check the wraps sit neatly before you trim anything away.

Why it works

  • One of the most dependable line-to-line joins, especially where diameters differ moderately
  • Can be tied without any tools, in the cold or in poor light

Where it lets you down

  • A large mismatch in diameter (thin braid to thick mono) reduces reliability compared with an FG or Alberto knot
  • Both knots must be seated evenly before the final pull or one can slip before the other locks
Shop

The tackle this knot ties

The knot itself costs nothing — it joins your line to the tackle you buy. This search shows the general category this knot is tied onto, never a named brand or model.

Shop fluorocarbon leader material
Alternatives

Knots that do a similar job

FG Knot →Alberto Knot →Blood Knot →
Used in

Fishing methods that use this knot

Trolling →Jerkbait / Glidebait →Spinning with Lures →Surf Casting →
Keep going

More knots worth learning

Improved Clinch Knot →Palomar Knot →Uni Knot →Blood Knot →Surgeon's Knot →Surgeon's Loop →Figure-of-Eight Loop →Perfection Loop →
Check the rules where you fish
Some waters restrict tackle or methods — barbless hooks, lead sinkers, certain rigs and line types. Confirm the rules of the water you are fishing before you use any rig or knot.