Line to Leader Knot

Tying light line to heavy leader is not much different from the line-to-line method. It may seem awkward at first because the end of the light line must be doubled to gain maximum strength. But the doubled portion is treated as a single strand and is actually easier to draw down.

Double the main line. Overlap the heavy leader and form the familiar Uni-Knot circle. Go around the strands and through the circle with the doubled end three times. Now, slip your finger into the loop. Holding all strands on the other side of the knot with the left hand, pull the loop with your finger until the knot is very snub.



A. Tie another Uni-Knot with the end of the heavy leader around both strands of line. Again, only three turns are required. Pull the second knot down snug.

B. Slide the knots together by pulling with opposing pressure on the main strand of leader and both strand of main line. Continue until no slippage is felt.

C. For final tightening, you will probably have to grip the line with a full hand grip, instead of using thumb-finger grips. This tie will consistently provide close to 100% of line strength if the first Uni-Knot is snugged completely tight, and if final tightening is done carefully and with steady hard pressure.


  • Curious

    What should the difference in line size be? Would this work with 20lb mono to 35lb fluoro?

  • FLSportsman

    Yes, in your case, it would work fine. But honestly, the difference in diameter between 20 pound mono and 35 pound fluorocarbon is not so great that you would even have to double the main line. Anglers only really run into issues when the main line and leader have dramatically different diameters. Anglers must then double the main line with a Spider hitch or Bimini twist (essentially doubling the diameter) to tie a secure (double) uni-knot that won't slip. For example, if using 10-pound braid and 30-pound-plus fluorocarbon leader, it's not a bad idea to double the main line before tying the uni-knot.