Surgeon's Join Knot
Surgeon's Join Knot
The easiest line-to-line connection. Joins two lines of any diameter with a simple double overhand knot — and it's actually stronger than the blood knot. Fast, reliable, and forgiving on the water.
Video by Sportfishing Report on YouTube
About the Surgeon's Join Knot
The Surgeon's Join Knot (or Surgeon's Knot) is the simplest and most forgiving line-to-line connection in fishing. It's nothing more than an overhand knot tied with both lines together — and adding a second pass (making it a double overhand) dramatically increases the knot's strength and security.
Unlike the Blood Knot, it works well even when the two lines are significantly different in diameter. It's not as compact as a Blood Knot, but tests equal or higher in breaking strength and is far easier and faster to tie, especially in the field.
Best Used For
Ideal applications
- ✓ Joining lines of any diameter combination
- ✓ Adding tippet to a fly leader quickly
- ✓ Fast field repairs
- ✓ Anyone new to fishing knots
Not ideal for
- ✗ Applications requiring the most compact possible knot
- ✗ Braided line (use double-uni instead)
Step-by-Step Instructions
Follow these 4 steps to tie the Surgeon's Join Knot. Watch the video above while following along.
Step 1: Overlap the lines
Lay 6 inches of the two line ends alongside each other, pointing in opposite directions. Hold them together as a single unit.
Step 2: Form a loop with both
Treating both lines as one, make a loop — pass the overlapped tag ends through the loop once.
Step 3: Pass through a second time
Without pulling tight, pass both tag ends through the loop a second time. This is what makes it a 'double' surgeon's knot.
Step 4: Wet and tighten
Wet the knot. Pull all four strands — both standing lines and both tag ends — simultaneously to draw the knot tight. Trim both tag ends close.
Pro Tips
- Pull all four strands at once — not just the standing lines
- Two passes through the loop (double) is significantly stronger than one
- For extra insurance on very light tippet, try a triple surgeon's (3 passes)
- Works for any diameter difference — even braid to heavy mono in a pinch
Common Mistakes
- Only making one pass through the loop (single overhand) — use double minimum
- Not pulling all four strands — the knot seats unevenly
- Not wetting before tightening
- Trimming tag ends before the knot is fully seated