The best seasons for fishing South Boulder Creek are summer and fall. During these periods, the middle section between the headwaters and the reservoir experiences large Baetis hatches. Below the reservoir, Mysis shrimp flies are particularly effective because the trout in the tailwater are well-fed on shrimp.

While winter fishing is feasible, the extreme cold and occasional frozen river sections can be too challenging for some anglers. Early spring fishing is tough due to runoff that often muddies the waters.

Best Flies for South Boulder Creek

Here are some recommended fly patterns for South Boulder Creek:

• Parachute Adams (grey #18)
• Griffith’s Gnat (black thread#18) 
• I Can See It Midge Fly (black #22)
• CDC Loopwing Quill Emerger (Dark #16,18,22)
• Mysis Shimp (white #18)
• Prince Nymph (peacock #12-18)
• Vernille San Juan Worm (clown Pink#16)
• Bead Head Brassie™(peacock #18 – 22)
• Brownstone (brown #14)
• Zebra midge (dark #20 – 24)
• Micro streamer (white, black, yellow, green #8) 

  Tips
  An 8-1/2 foot, 4-weight fly rod with floating line is ideal for fishing dry flies and nymphs on South Boulder Creek. A tapered 9-foot leader with a tippet size of 3X to 5X, matching the flies you are using, is a standard setup.
  

  Regulations
  Pay attention to the posted signs indicating private property boundaries on South Boulder Creek, as public access state land borders many ranches and other private properties.
  Anglers should also be mindful that walking along the train tracks is considered trespassing on Amtrak property, and both passenger and freight trains pass by frequently.
  On public land above Gross Reservoir and most of the tailwater, anglers should adhere to the standard fishing regulations set by the Colorado Division of Wildlife. However, note that access is restricted in the area immediately below the reservoir.
  Planning Tips
  The best deals are usually found by flying into Denver and then driving to Boulder or Golden for lodging.
  There are various accommodation options, including traditional hotels and motels, ski lodges, ranches, and local bed and breakfasts that cater to fishing, hiking, and hunting enthusiasts all year round.
  Since both cities are popular tourist destinations throughout the year, it's important to book well in advance if you plan to visit.
  Additionally, be sure to check local vacation rental listings, as many offer discounts during the off-season for anglers with flexible travel plans.