2016 One Fly Event Rules

Updated for 2016

Print Version: One Fly Rules (Revised 2016)

  1. Each team will consist of four fishing contestants. Alternate contestants may substitute on a daily basis.
  2. Only one member of a team may be a professional fulltime or part-time fresh or salt water fly fishing guide or captain. A professional is defined as anyone who, within the last 5 years, has received income for services performed as a guide or captain.
  3. Two contestants will fish in each boat and will be from different teams.



  1. Contestants will furnish their own fly-fishing equipment. Each contestant may bring one or two fly rods in the boat.
  2. Type of fly rod and reel is the choice of each contestant.
  3. The use of fly floatant or other accessories will be at the discretion of the contestant. Only floating fly lines are permitted. Sinking leaders six feet or less in length are permitted.
  4. Use of motors on boats during event hours is prohibited.
  5. No real or artificial fish attractants, such as scents, are allowed.



  1. Any conventional fly pattern (dry, wet, nymph, streamer, etc.) may be used as long as it is no larger than size #6 and is 3x or shorter in length. The guide will compare each competition fly to a template. (See below)


Diameter of hood can be no bigger

Nor longer than image shown.

Image based on Dai Riki #710,

size 6 with 3x shank.



  1. The fly may have one bead, cone or dumbbell eye set and may have lead or non-lead wire used in the construction of the fly. Non-lead weight may be added to the leader. Molded metal heads (jigs) are not allowed. Tube flies are prohibited.
  2. Flies must be tied on a single barbless hook, or on a hook with the barb pushed down.
  3. Contestants will choose the fly they will use each day. A different fly and a different pattern may be used on the second day of the event.
  4. The guide must approve the contestant’s fly selection before 8:30am. The guide’s judgment regarding the legality of the fly, its size and barbless nature are considered final.
  5. Repair of flies may only be done with the use of glue or any adhesive. Any re-tying of the fly with thread or fly tying materials is prohibited. Broken hooks may be honed or filed to a usable sharpness via any sharpening tool.
  6. Traditional strike indicators are allowed. Flies, even those with broken hooks, are not allowed to be used as an indicator. Only a single fly may be attached to the leader.



  1. Federal and state rules and regulations governing the waters to be fished will be strictly observed.

AIS inspection requirements: Any watercraft that has been in a water infested with zebra/quagga mussels within the last 30 days, is required to undergo a mandatory inspection by an authorized inspector prior to launching (this includes pre-contest boating). Participants violating that regulation will be disqualified.


Violation of WGF regulations: All contestants must abide by all Wyoming Game and Fish regulations concerning fishing, aquatic invasive species and boating. Any participant found to violate any Game and Fish regulation from 8AM Friday through 4:30 PM Sunday will be disqualified.

  1. All main river channels are fishable.
  2. All trout species will be counted in the scoring. No whitefish will be counted.
  3. Fishing hours on the Snake River will be from 8:30am until 4:30pm on day 1, and from 8:30am until 4:00pm on day 2. Fishing hours on the South Fork River for both days will be from 8:30am until 4:00pm. Guides are the official timekeepers and judges.
  4. Only legal BLM, Forest Service, National Park, or One Fly-approved river accesses may be used. A list of allowed accesses will be available to guides at their required meeting before the One Fly.
  5. Contestants may not float through any stretch of water more than once except that a guide may maneuver a boat upstream to fish a particular run again (for example, by back-rowing).
  6. Guides or contestants may not walk nor row upstream from their assigned put-in, or downstream from their assigned take-out, to fish. This applies to both sides of the river.
  7. The Upper South Fork section will end at the Spring Creek Bridge. The Middle South Fork section will begin at the Spring Creek Bridge and take out at Eagle. The Lower South Fork will put in at Eagle and take out at Byington.
  8. A contestant’s assigned fishing venue and guide shall not be altered. Unless specifically approved in advance by the Rules Committee, any variance from these assignments will disqualify the contestant from that day’s fishing.
  9. With the permission of the fisherman who has a fish “on the line”, guides or boat partners may assist in landing any fish to be scored in the event.
  10. If a contestant’s fly becomes caught in brush or in a snag, it may be recovered and reattached to the leader. The contestant may continue fishing in the event. The contestant can be disqualified by the guide for any unsafe practice used to retrieve a fly.
  11. Daily scoring ends for the contestant when his official fly becomes irretrievably lost. That person may continue to fish for the remainder of that day, but no fish caught after the contest fly is lost will count for that day’s scoring.
  12. Fishing contestants will mutually agree on boat position assignments (front and back) so that each angler spends one half of the fishing day in the front of the boat. This schedule continues even if an angler loses his fly.
  13. The person in the front of the boat will, within reason, have the choice of boat position, such as right bank vs. left bank, casting distances, etc., or stopping the boat to fish.
  14. Contestants must wear (and have fastened) their life vests while fishing or being transported on the river.
  15. Guides will be furnished daily a Rules Violation Sheet, where the guide will write out any violation, have it signed by a witness (other person in the boat) and must turn the Violation Sheet into the Rules Committee within 2 hours after landing. The three (3) person Rules Committee who will be at the scoring area will consist of two One Fly board members and a guide representative. The Committee will rule in writing on the violation within one hour after receiving it. Penalties will vary with the violation, from sanctions, to nullifying daily scores, to disqualification from the event. Violations will be considered only from the guide who is guiding the violator.
  16. Q. Trout caught from tributary streams which enter the primary river will be deemed eligible for scoring if the fly is cast no more than 100 ft. upstream into the tributary from the high mark of the natural stream bed of the main river. Any contestant who is trespassing on a tributary stream, which is not legal for fishing, will be disqualified from the event.



The One Fly has adjusted its scoring procedures to reduce the handling of our native trout.

  1. To be counted in the score, the release of a caught trout must be witnessed by the guide. Each of these trout will have a value of two points. If the angler or the guide touches the leader while a fish is “on”, then that fish is counted as two points.
  2. Each contestant will be allowed to select eight (8) trout to measure during the day. Six (6) of these fish will have a bonus score. All trout not selected for measurement will be released immediately, preferably without removing them from the water.
  3. C.     Measurement of trout shall be done by the Guide while the trout is in the water whenever possible. The Guide should measure the trout with the fish trough provided to the Guide, a Fishscale on the rod or net handle, a ruler, tape measure or like device. Fish are to be measured from the tip of the nose to the tip of the relaxed tail. The tail of the trout should not be pinched. All trout should be measured to the nearest 1/4 inch. Measurements should not be rounded up by the guides. This is to ensure accurate measurements for the biggest fish competition. In signing the scorecard, the contestant understands that this represents only an estimate of their final score. Scores will be finalized, by the scoring committee when necessary, due to rounding of fish length and/or incorrect addition of total points.
  4. Each of the six fish for bonus scoring by a contestant will be scored as follows:



Less than 12″ + 2 points

12″– 2 points + 10points

13″– 2 points + 20 points

14″– 2 points + 30 points

15″– 2 points + 40 points

16″– 2 points + 60 points

17″– 2 points + 80 points

18″– 2 points + 100 points

19″– 2 points + 125 points

20″– 2 points + 150 points

21″– 2 points + 175 points

22″– 2 points + 200 points

Add 50 points per inch  for trout over 22 inches

Other Bonus Points

If total number of trout  landed is between:

30-39  –  Add 50 bonus points

40-49 –    Add 100 bonus points

   50+ – Add 150 bonus points


  1. 25 points will be awarded to a contestant each day that contestant keeps his competition fly all day.
  2. A penalty will be assessed for any fish killed or ruled by the guide to be unable to survive. Each of these fish will be measured and the scored value of that trout will be subtracted from the angler’s score. That trout will not be counted against the daily limit of six measured trout.

These rules are subject to change and modification as directed by the One Fly Board of Directors and Rules Committee.


Read the One Fly Etiquette page for helpful hints to make your one fly experience more enjoyable.

Helpful Hints To Make Your One Fly Experience More Enjoyable