Early Spring Fly Fishing on the Big Thompson River
As winter begins to fade in Estes Park, the Big Thompson River transitions into one of its most technical and rewarding fishing seasons. April brings longer days, slightly warmer temperatures, and the first consistent insect activity of the year.
While conditions can still feel like winter, anglers who adjust their approach can find excellent fishing—especially on the tailwater below Lake Estes.
What to Expect in April
Early spring is defined by low, clear flows and selective trout. Fish remain cautious but begin feeding more consistently as water temperatures slowly rise.
The most important change this time of year is the emergence of Blue-Winged Olives (BWOs), which begin to supplement the ever-present midge hatch.
Key Conditions:
- Cold mornings, improving midday fishing
- Clear water requiring stealth
- Increased activity on cloudy afternoons
Best Areas to Fish
Below Lake Estes (Tailwater)
This stretch offers the most consistent fishing thanks to stable flows and slightly warmer water. Trout hold in deeper runs, seams, and tailouts.
Big Thompson Canyon
Fishing improves on warmer days. Focus on slower water and protected sections where ice has receded.
Best Flies for Early Spring
Nymphs:
- Zebra Midge (#20–24)
- RS2 (#20–24)
- Pheasant Tail (#18–22)
Emergers:
- Foam Wing RS2
- Barr’s Emerger
Dry Flies (Afternoon Windows):
- BWO (#18–22)
- Parachute Adams
Streamers:
- Small olive or black Woolly Buggers
Tips for Success
- Fish late morning through mid-afternoon (10am–3pm)
- Use 5x–6x tippet in clear water
- Focus on slow seams and transition zones
- Prioritize dead drift presentations
Why Fish the Big Thompson in Spring?
Early spring rewards anglers who enjoy technical fishing and solitude. With fewer crowds and increasingly active trout, this is one of the most underrated times to fish in Estes Park.