Nail Knot
The standard fly fishing knot for connecting fly line to leader. Creates a smooth, low-profile connection that passes through rod guides cleanly — a must-know for any fly angler.
Video by Sportfishing Report on YouTube
The Nail Knot is a intermediate leader connection knot that retains approximately 90% of line strength and takes about 2 min to tie. It's ideal for Fly line to leader butt connection, Fly line to backing (heavier version), and Low-profile connections that must pass through guides on Fly line to leader line. To tie it: position the tube, lay the leader alongside, wrap 6 times, thread through the tube, then wet and tighten.
About the Nail Knot
The Nail Knot is the traditional fly fishing connection for attaching the butt end of a leader directly to the fly line. The result is a clean, low-profile joint that passes through rod guides without catching — essential for smooth presentations and long casts.
Originally tied using a nail as a guide (hence the name), modern anglers use a thin tube, a needle, or a commercial nail knot tool. Once mastered, it creates one of the most dependable fly line-to-leader connections available.
Best Used For
Ideal applications
- ✓ Fly line to leader butt connection
- ✓ Fly line to backing (heavier version)
- ✓ Low-profile connections that must pass through guides
Not ideal for
- ✗ Quick changes on the water (not fast to tie)
- ✗ Situations requiring a loop-to-loop connection
Step-by-Step Instructions
Follow these 5 steps to tie the Nail Knot. Watch the video above while following along.
Step 1: Position the tube
Hold a thin hollow tube (or needle) alongside the fly line, pointing toward the line end. This is your guide for tying.
Step 2: Lay the leader alongside
Hold the leader parallel to the fly line and tube, with 12 inches of tag end extending past the fly line tip.
Step 3: Wrap 6 times
Wrap the leader tag end tightly around the tube, fly line, and standing leader 6 times, moving toward the fly line tip.
Step 4: Thread through the tube
Pass the leader tag end back through the hollow tube. Then slide the tube out carefully while pinching the wraps.
Step 5: Wet and tighten
Wet the knot thoroughly. Pull the tag end and standing leader simultaneously to seat the wraps tightly around the fly line. Trim both tag ends flush.
Pro Tips
- A commercial nail knot tool makes this much easier
- Six to eight wraps creates the right balance of grip and slimness
- Wet generously before pulling — mono seats much better on fly line when wet
- Trim both tag ends as close as possible for a smooth, snagle-free finish
Common Mistakes
- Too few wraps — knot will slide on the slick fly line coating
- Loose, uneven wraps that don't compress properly
- Trimming tag ends before fully seating the knot
- Not using a tube or tool — threading by hand is very difficult