If you decided to learn how to tie just one saltwater fishing knot - make sure it's the Uni-Knot!
As one of the easiest fishing knots to tie, and with a breaking strength only slightly less than the line itÂ’s tied in, you can use it to attach the line to your swivels, hooks and lures (although the Rapala Knot is a better knot to use for lures) and also to join two lines together.
As such, many sea anglers tie two in tandem for connecting their mainline to their leader.
Stage 1
First, pass a line through the eye of the hook and form a loop as shown here.
Stage 2
Now make at least four turns (more for light lines) around both strands and through the loop. Wet the knot with saliva and start tightening it by first pulling on the tag end in the direction of the arrow.
Stage 3
Then, with the knot now well consolidated, snip the end off close and pull on the line to slide it down towards the hook.
Stage 4
And that's it, the finished knot, as it's tied for attaching the line to swivels, hooks and lures.
Artwork by Andrew Simpson
The following tandem version is a simple way of joining two lines of similar diameters. Each line ties a Uni Knot around the other before the two knots are pulled together to complete the connection.
In this form it's often called, for obvious reasons, the Leader Knot.

If you like the idea of having the most popular sea fishing knots all together in one place for easy reference, this handy little pocket guide is just the thing.
It sets out in step-by-step instructions and nicely drawn sketches how to tie all the knots you'll ever be likely to need - 18 of them in all.
Being spiral bound it opens flat, leaving both hands free to tie the knot - and it's waterproof!
Connecting Hooks, Swivels and Lures to Single-Strand Wire Line
Forming a Stand-Off dropper Loop in Mono Line
Forming a Reinforced Loop in Mono Line
Connecting Mono Line Directly to Single-Strand Wire Line