How to Use a San Juan Worm

How to Use a San Juan Worm | Jackson Hole Fly Company

Consistently consistent...but great after rain and in high water.

Worm patterns are versatile and effective staple in the fly fishing world and can be used year-round, but are most effective after a big rain or in higher water. The San Juan Worm and Ultra Worm are simple patterns that imitate aquatic worms commonly found in most trout waters, especially in spring when the runoff scours stream banks and loads rivers with real worms.

In most cases, you should position your chosen worm pattern, whether it be the San Juan Worm or the more intricate Ultra Worm, as the primary nymph in a tandem nymph rig. This setup not only increases your chances of a successful catch but also mimics the natural movement of worms in the water, making it an irresistible target for trout.

When it comes to adapting your rig for different water conditions, a few tweaks can make a significant difference. In deeper and faster-flowing waters, it becomes essential to modify your rig to ensure your worm pattern sinks to the optimal depth. This can be achieved by adding weight to your rig. Alternatively, for a more streamlined approach, you might consider using beaded versions of the Ultra Worm. These beaded variants not only sink more efficiently but also add an extra element of allure to the worm, catching the light and drawing attention from curious trout.



To effectively use the San Juan Worm, adopt a slow, deep, dead-drift approach along seams and runs, much like you would with other nymphs. Don't limit yourself to just the edges of banks or boulders. Aquatic worms naturally inhabit the river's plant life, so getting your fly as close to the riverbed as possible increases your chances of a catch. Adaptability is key – match the worm's color and size to the water you're fishing in. The versatility of the San Juan Worm not only makes it a reliable choice but also adds a fun dimension to your fishing experience.

Setting Up Your Tandem Nymph Rig

Here's a simple guide to setting up an effective tandem nymph rig:

  • Leader With A Strike Indicator: This is your starting point.
  • Split-Shot Weights: Position these just above the knot connecting the first section of tippet to your leader. This placement prevents sliding and maintains the desired depth.
  • First Tippet: Connects to the leader.
  • San Juan Worm: Your primary nymph.
  • Second Tippet: Attach this to the San Juan Worm. You have two options here: connect to the hook shank for a standard setup, or for added movement, tie it through the hook’s eye.
  • Trailing Nymph: This could be another nymph or, for the adventurous, a second San Juan Worm!

Incorporating worm patterns into your fly fishing arsenal is a surefire way to enhance your catch rate. Here are three worm patterns to always have on hand:




San Juan Worm Red: This worm imitation represents an aquatic worm which is a prevalant food source for Trout. More than anything, it is just a good attractor pattern that Trout really seem to like.




San Juan Wire Worm Chartreuse: The living worms tend to be of neutral colours however time and experience have demonstrated that Trout frequently find an added attraction to the extra little colouring. Trout simply cannot resist this tempting imitation when it is put before them.


Double Bead "Ron Burgundy" Ultra Worm is a pattern that is an offshoot of the popular bead Ultra Worm. The double bead allows this worm to sink faster. The burgundy color is great for muddy water as the fish see purple as a dark object that stands out better.


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