
| What | When | Key Numbers |
|---|---|---|
| Stream fishing | Late June - October | Fish 6-10"; water temps 45-55°F ideal |
| Alpine lakes | July - October | Ice-out 10,000 ft late June; 10,500+ ft mid-July |
| Off-season tailwater | November - May | Big Thompson below Lake Estes; 15-30 CFS winter |
| Glacier Gorge parking | Arrive before 6am | Fills before dawn on summer weekends |
| Wild Basin parking | Arrive before 8am | Fills by 8:15am; use shuttle after |
| Timed entry permits | May 23 - Oct 19 (2025) | Bear Lake 5am-6pm; rest of park 9am-2pm |
| Downstream gauge | Big Thompson at Drake | 100-150 CFS = park streams fishable |
| Fly shop | Kirk's Flyshop | (970) 586-2110, 230 E Elkhorn Ave |
Dec 28: Off-season for park streams—most frozen or too cold. Focus on the Big Thompson tailwater below Lake Estes (15-30 CFS winter flows) for year-round fishing. Expect midge and occasional BWO hatches midday. Inside the park: ice, snow, limited access. Trail Ridge Road closed. No timed entry permits required in winter. Target 11am-3pm for best tailwater action. Kirk's Flyshop in Estes Park has current conditions.
Rocky Mountain National Park's east side offers something different from the big tailwaters and gold medal rivers elsewhere in Colorado. This is small stream fishing in a national park setting—intimate water, wild trout, and scenery that makes up for any fish you don't catch. The trout here aren't large by Colorado standards (most run 6-10 inches), but they're wild, willing, and you'll be casting in some of the most beautiful terrain in the state.
The east side drains into the Big Thompson and St. Vrain watersheds. The major fishable waters include the Big Thompson River (Moraine Park), Glacier Creek, Fall River, and dozens of alpine lakes accessible by trail. You'll find four trout species—brown, brook, rainbow, and greenback cutthroat—with brook trout dominating the higher elevations.
Two things to know upfront: the fish run small, and the logistics require planning. Parking lots fill before dawn on summer weekends, and the timed entry permit system adds another layer. But if you want to catch wild trout in alpine settings with the Continental Divide as your backdrop, this is the place.
Go to: Big Thompson River in Moraine Park
Why: Easiest parking situation of the prime fishing spots. The Cub Lake Trailhead lot holds more cars than Glacier Gorge and fills later (usually by 7:30-8am vs. before dawn). Walk 0.25 miles to the river through open meadow.
Note: This is Bear Lake corridor—you'll need a timed entry permit (May 23 - Oct 19) unless you arrive before 5am.
Pro tip: The trees near the Cub Lake Trailhead provide cover for easier approaches to spooky fish. The open meadow sections downstream look appealing but the fish see you coming from 50 feet away.
What to bring: 3-weight or 4-weight rod (7-8 feet), small box with Elk Hair Caddis (14-18), Parachute Adams (14-18), Pheasant Tail nymphs (16-20), and a few foam ants.
When to fish: 10am-3pm. At this elevation (8,000+ ft), trout feed during the warmest part of the day. Early morning is overrated here—water temps are too cold and fish are sluggish.
Real trip planning means knowing what to do when conditions aren't perfect.
Wind over 20 mph makes alpine lake fishing miserable. Fish still rise, but casting becomes a nightmare and presentation suffers.
Plan B: Drop to a protected stream. Glacier Creek runs through a valley with tree cover on both sides—fishable in wind that would blow you off Sky Pond. The section from Glacier Basin Campground downstream offers easy access and willing brookies.
Better option: The Loch (Loch Vale) sits in a cirque with cliffs on three sides. The coves along the eastern shore stay protected even when wind rips across the main lake. If you're already hiking toward Sky Pond and conditions deteriorate, The Loch is your fallback.
Spring runoff typically runs late May through late June. Streams run high, cold, and muddy.
Plan B: Check the Big Thompson River below Lake Estes. This tailwater section stays fishable year-round because the dam filters sediment. When it's reading 100-150 CFS, conditions are usually manageable. If the gauge shows 200+ CFS with rising trend, park streams are likely unfishable.
Alternative: Sprague Lake offers easy access and warmest water temps in the Bear Lake corridor. It clears earlier than moving water and fishes well with small streamers and leeches even when streams are off-color.
Bear Lake permits sell out fast—sometimes within minutes of release.
Plan B: Fish Fall River or Wild Basin instead. Both operate under the standard timed entry system (9am-2pm only), which is easier to get. Better yet, arrive before 9am—no permit required.
Best alternative: Wild Basin sees a fraction of Bear Lake corridor traffic. The fishing quality is comparable, and the 8am parking fill time gives you more flexibility than Glacier Gorge's pre-dawn scramble.
On summer weekends, Glacier Gorge fills before 6am. Bear Lake by 8am. Wild Basin by 8:15am.
Solutions:
Rare in RMNP, but possible in August during heat waves, especially in shallow meadow sections.
Guideline: Trout stress above 65°F and stop feeding above 68°F. If you're catching fish that seem lethargic, check water temp. Above 65°F, stop fishing—stressed fish have higher mortality even when released properly.
Solution: Move higher. Glacier Creek and the alpine lakes stay cold all summer. Moraine Park's meadow sections warm fastest; the shaded runs upstream toward Forest Canyon stay cooler.
This is the planning piece that trips up first-time visitors. From May 23 through mid-October, you need a timed entry permit to access the park during peak hours.
Two Permit Types for 2025:
| Permit Type | When Required | What It Covers |
|---|---|---|
| Timed Entry + Bear Lake Road | 5am-6pm daily (May 23 - Oct 19) | Bear Lake corridor including Moraine Park, Sprague Lake, Glacier Gorge, Bear Lake |
| Timed Entry (rest of park) | 9am-2pm daily (May 23 - Oct 13) | Wild Basin, Fall River, west side—everywhere except Bear Lake Road |
Key Details:
Fishing Strategy: If you can't get a Bear Lake corridor permit, fish Fall River or Wild Basin instead. Or skip the permit entirely by arriving before 5am (Bear Lake) or before 9am (elsewhere)—you'll need to anyway if you want parking.
RMNP has park-specific rules that differ from standard Colorado regulations. Know these before you fish.
License: Valid Colorado fishing license required for ages 16+. Available at Colorado Parks & Wildlife, local fly shops, or by phone at 800-244-5613. One-day licenses run $17.35 (non-resident). Pick one up at Kirk's Flyshop before you enter the park.
General Rules:
Catch Limits: The possession limit structure prioritizes brook trout removal:
Translation: The park wants you to keep brook trout, especially small ones. They're invasive and compete with native greenbacks.
Catch-and-Release Waters (Barbless Hooks Required): Waters supporting greenback cutthroat are catch-and-release only: Adams Lake, Arrowhead Lake, Hidden Valley Creek, Hunters Creek, Ouzel Lake, The Loch, Sky Pond, and others. Full list at NPS. When in doubt, use barbless—you'll release most fish anyway given the size.
Closed Waters: Bear Lake, Kettle Tarn, and portions of Shadow Mountain Reservoir (Oct 1-Dec 31) are closed to fishing.
Gear Disinfection: If you've fished outside the park or are moving between drainages more than 2.5 miles apart, disinfect your gear with 10% bleach solution. This protects against whirling disease and other aquatic invasives. Felt soles are strongly discouraged—use rubber.
RMNP streams are too small for dedicated gauges, but you can infer conditions from downstream water.
Reference Gauge: Big Thompson River at Drake (below the park)
| Gauge Reading | What It Means for Park Streams |
|---|---|
| 50-100 CFS | Low water. Moraine Park fishable but skinny. Fish spooky in clear water. Best conditions for alpine lakes. |
| 100-150 CFS | Ideal. Good water in all park streams. This is what you want. |
| 150-250 CFS | Elevated but fishable. Stick to slower pools and edges. |
| 250-400 CFS | High water. Meadow sections may be wadeable with caution; pocket water difficult. Consider alpine lakes instead. |
| 400+ CFS | Blown out. Park streams likely unfishable. Fish the tailwater below Lake Estes or wait for flows to drop. |
Seasonal Pattern:
The Big Thompson is RMNP's signature east-side fishery. It begins at Forest Canyon below the Continental Divide and flows through Moraine Park—a wide glacial valley where the river meanders through meadows before dropping toward Estes Park. This is classic mountain meadow fishing with easy wading and sweeping views.
Character: Slow-moving meadow water with undercut banks, riffles, pools, and gravel runs. The river splits into several braided channels through Moraine Park—locals call them all "the Big T" regardless of which channel you're on. Fish hold against structure and in deeper bends. Open terrain means easy backcasts but extremely spooky fish.
Fish: Wild brown trout and brook trout, averaging 6-10 inches. The occasional brown to 14+ inches holds in deeper pools and undercuts—these fish didn't get big by being stupid. Approaching Forest Canyon, greenback cutthroat become more common but require longer hikes.
Water Temperature: Moraine Park's open meadow sections warm fastest in the park. Expect 50-58°F in July-August during midday. The shaded runs upstream stay 5-8 degrees cooler.
Access Points:
| Access | Parking Situation | Walk to Water | Notes |
|---|---|---|---|
| Cub Lake Trailhead | ~50 cars; fills 7:30-8am weekends | 0.25 miles | Best parking-to-fishing ratio. Trees provide approach cover. |
| Fern Lake Road | Multiple pull-offs; rarely all full | Roadside | Road closed to vehicles in winter. Multiple access points—scout from the road. |
| Moraine Park Campground | Campers only | Walk-in | If you're camping, you have built-in dawn access before day-use crowds. |
Where to Find Bigger Fish:
Browns hold in structure. Focus on:
Don't waste time on the obvious shallow riffles in the middle of the meadow—that's where beginners fish and where fish see the most pressure.
Best Approach:
Flow Note: The Big Thompson inside the park is not dam-controlled. Spring runoff (May-June) can blow it out completely; typically clears by late June. After heavy summer thunderstorms, give it 24-48 hours to clear.
Glacier Creek tumbles from the glaciers below Longs Peak through the Glacier Basin area, joining the Big Thompson downstream. This is freestone pocket water—fast riffles, boulder gardens, and plunge pools—requiring more technical fishing than Moraine Park's meadow water.
Character: Classic alpine pocket water with fast-moving riffles, boulders, and holes. Colder and clearer than the Big Thompson (typically 45-52°F even in August), with a steeper gradient. Much of it runs right along the road—easy to access, but also easy to dismiss as "too small." Don't. These fish eat.
Fish: Four species: brown, brook, cutthroat, and rainbow trout. One of the few places in the park where you might catch all four in a day—locals call it the "grand slam." Fish average 6-10 inches with occasional 12-inchers in deeper plunge pools.
Access:
| Access | Parking Situation | Notes |
|---|---|---|
| Glacier Gorge Trailhead | ~50 cars; fills before 6am on summer weekends | Primary access for Mills Lake, The Loch, Sky Pond. Park and Ride shuttle is your backup. |
| Glacier Basin Campground | Campers + limited day-use | Walk downstream from camp for less pressure and willing fish. |
| Bear Lake Road pull-offs | Various small lots | Fish the roadside sections everyone else drives past. No waders needed—wet wade or fish from rocks. |
Fishing Approach:
Why Fish Here When It's Windy: Glacier Creek runs through a protected valley with tree cover. When alpine lakes are getting hammered by wind (common afternoons), drop down here. You'll catch fish instead of fighting your fly line.
Best Times: July through September after snowmelt clears. Glacier Creek can run high and cold into July in big snow years—check the downstream gauge before committing to the hike.
Fall River drains the northwestern quadrant of the east side, flowing through Horseshoe Park before leaving the park near the Fall River entrance. It's smaller and more intimate than the Big Thompson, with spooky wild trout that reward stealth.
Character: Small mountain stream with tight casting lanes, meadow runs, and pocket water. The section through Horseshoe Park offers open meadow fishing similar to Moraine Park; above Alluvial Fan the character becomes more alpine with faster water.
Fish: Brook trout and brown trout, with greenback cutthroat in the upper reaches. Most fish run 6-9 inches—don't expect size, but they hit eagerly. These are the least-pressured fish on the east side.
Why Fish Here:
Access:
| Access | Parking Situation | Notes |
|---|---|---|
| Alluvial Fan Trailhead | ~40 cars; rarely full | Park at east or west lot; walk to water. The fan itself is worth seeing—created by a 1982 dam failure. |
| Horseshoe Park pull-offs | Roadside; always available | Multiple spots along Trail Ridge Road. Pick one that looks good. |
| Roaring River confluence | Near Alluvial Fan | Where Roaring River enters Fall River; fish stack up in the deeper water below the confluence. |
Fishing Approach:
The alpine lakes of RMNP represent some of the best high-country fishing in Colorado. These are destination trips—you'll work for the fishing—but the combination of scenery, solitude, and wild cutthroat makes them worth the effort.
General Rule: The harder the hike, the better the fishing. This is true everywhere but especially here.
The most popular alpine lake destination on the east side—and for good reason. A moderate hike leads to a cirque lake sheltered by alpine cliffs. The protection from wind makes this ideal for calm-water dry fly fishing when other lakes are getting hammered.
Details:
Why The Loch Works When Others Don't: The cirque walls on three sides block wind. Even when Sky Pond above is unfishable, The Loch's eastern coves stay protected. If your forecast shows afternoon wind (which it usually does), plan to fish The Loch, not Sky Pond.
Fishing Notes: Fish cruise visible in the clear water—spend 5 minutes watching before you cast. They follow predictable routes near shore. Concentrate on:
Small ants, beetles, and black midges produce consistently. These fish aren't leader-shy—5X is fine.
Above Loch Vale, a scramble up a short cliff leads to Sky Pond—one of the park's most dramatic settings. Taylor Glacier hangs above the far shore. The fishing can be exceptional, but conditions need to cooperate.
Details:
Access Note: The route from The Loch to Sky Pond involves a short Class 3 scramble beside Timberline Falls. Not technical climbing, but you'll use your hands. Poles stow on your pack.
The Wind Problem: Sky Pond sits in an exposed bowl. Afternoon winds regularly hit 20-30 mph, making surface fishing impossible. Fish here in the morning or not at all. Plan to arrive at the lake by 9am, fish until wind picks up (usually 11am-noon), then retreat to The Loch for afternoon fishing.
Closer and easier than Loch Vale, Mills Lake sits below the east face of Longs Peak—the classic postcard view. Good numbers of brook trout with some cutthroat mixed in.
Details:
Best For: Anglers who want alpine lake scenery without the longer hike to The Loch. Also good for families or less-experienced hikers. The fish are willing and the Longs Peak backdrop is iconic.
Wild Basin offers fewer crowds than the Bear Lake corridor. The tradeoff: longer hikes to quality water and a separate entrance (Highway 7 south of Estes Park).
| Lake | Distance (RT) | Elevation | Fish | Notes |
|---|---|---|---|---|
| Ouzel Lake | 10 miles | 10,020 ft | Brook trout | Excellent water quality; consistent fishing. Named for the water ouzel (dipper) birds you'll see. |
| Thunder Lake | 13.6 miles | 10,574 ft | Cutthroat | One of the park's most remote lakes; outstanding fishing for those willing to work. Overnight backpack recommended. |
| Calypso Cascades | 3.6 miles | 9,200 ft | Brook trout | Shorter option; fish the pools below the falls. Good family destination. |
Wild Basin Access: From Highway 7 south of Estes Park, turn at Wild Basin sign. Drive 2 miles on dirt road to trailhead.
Timing: Ice-out varies by elevation and snowpack year.
Best Conditions: Calm mornings and evenings when fish rise. Wind over 20 mph makes dry fly fishing miserable—switch to streamers stripped slowly, or drop to a protected stream.
Water Temperature: Alpine lakes run 45-55°F even in August. Fish are active all day; the "midday lull" that affects lower-elevation water doesn't happen here.
Flies That Work:
Approach: Fish cruise predictable routes near shore, often in 2-4 feet of water. Watch before casting. Position yourself where cruisers will pass within casting range, then lead them by 3-4 feet. Don't cast at fish—cast where fish will be.
RMNP waters support healthy insect populations despite the elevation. The key difference from lower-elevation rivers: hatches are compressed into a shorter season and smaller insects dominate.
| Month | Primary Hatches | Key Flies | Notes |
|---|---|---|---|
| Late June | Caddis, Yellow Sallies | Elk Hair Caddis (14-18), Yellow Stimulator (14-16) | Runoff may still affect lower streams |
| July | Caddis, PMDs, stoneflies | Parachute Adams (14-18), PMD Comparadun (16-18), Golden Stone (8-12) | Prime time. Best dry fly fishing of the year. |
| August | Caddis, terrestrials, BWOs begin | Foam Ant (14-18), Foam Beetle (14-16), Parachute BWO (18-22) | Terrestrials become critical; ants especially. |
| September | BWOs, midges | RS2 (20-22), Griffith's Gnat (18-22), Zebra Midge (20-24) | Smaller flies, longer leaders. Fish are fat and selective. |
| October | Midges, BWOs | Black Beauty (20-22), Mercury Midge (20-24), BWO Emerger (20-22) | Cold mornings; fish 10am-3pm. |
Dries (12 flies minimum):
Terrestrials (6 flies)—Don't skip these:
Nymphs (8 flies):
Midges (6 flies):
For Alpine Lakes (add):
Most RMNP waters freeze or blow out during the off-season, but the Big Thompson River below Lake Estes offers year-round fishing just outside the park. This tailwater stays ice-free thanks to the dam's regulated releases.
Location: Immediately below Olympus Dam, accessible via Mall Road in Estes Park. The catch-and-release section extends 9 miles downstream to Waltonia Bridge.
Access: Park at the public lot on Mall Road and walk to the river. Multiple pull-offs along Highway 34 provide additional access downstream. Viestenz-Smith Park offers another established access point.
Why Fish Here Off-Season:
The Catch: This water gets pressured—even in winter. Fish see a lot of flies. Expect technical fishing: long leaders (12+ feet), light tippet (6X-7X), and small patterns (18-24). If you want solitude, this isn't it. If you want to catch fish in December, this is your best option near Estes Park.
Winter Flows: Typically 15-30 CFS through winter. Check Colorado flows on RiverReports before driving.
Winter Fly Box:
Gear: Chest waders essential—you'll be standing in 32°F water. Dress warm; fish the warmest part of the day (11am-3pm).
Regulations: Catch-and-release, artificial flies and lures only from Lake Estes to Waltonia Bridge.
Not every spot lives up to the hype. Here's straight talk on a few locations.
The hype: Easy access, multiple trout species, wheelchair-accessible, great for beginners.
The reality: All true—but it's also the most heavily pressured water in the park. Every tourist with a fishing license stops here. The fish have seen every fly in the box. You'll catch fish, but they're educated and the setting feels more "park attraction" than "backcountry solitude."
Verdict: Good for families, kids, or mobility-limited anglers. Skip it if you're an experienced fly fisher looking for quality water. The 30-minute drive to Wild Basin or the 0.25-mile walk to Moraine Park offers dramatically better fishing.
The hype: Year-round fishing, wild browns, great winter option.
The reality: Excellent fish in heavily pressured water. Even in January, you'll share the river with other anglers. The fish are smart—they've been caught and released dozens of times. Technical fishing required.
Verdict: Worth it for off-season fishing when no other options exist. Frustrating if you expect easy fishing. Bring your A-game and small flies.
The hype: Classic meadow stream, easy access, beautiful scenery.
The reality: The first 100 yards of river visible from parking areas gets hammered. Fish are spooky to the point of neurotic. Beginners wade right through the best holding water without realizing it.
Verdict: Walk further. The productive water is 0.5+ miles from parking. Fish the structure (undercuts, beaver dams, confluences) rather than the pretty-looking riffles everyone else fishes. Or head to Fall River where pressure is lighter.
Can you fish it? No. Bear Lake is closed to fishing. Don't waste time wondering—it's explicitly prohibited.
The go-to shop in Estes Park. They've been guiding RMNP waters for 20+ years and post weekly fishing reports. Stop in for current conditions and permit strategy—they deal with the logistics questions daily.
Family-run operation with 15+ years on RMNP waters. All trips private—groups never combined. Good option if you want personalized instruction.
Fort Collins-based shop with RMNP expertise. Their guides know the backcountry lakes that most Estes Park guides don't fish regularly.
Offers both fly fishing and conventional tackle trips. Good option for mixed groups where not everyone fly fishes.
The greenback cutthroat is Colorado's state fish—and its story is wilder than most anglers realize.
The Genetics Plot Twist: In 2007, genetic testing revealed that fish CPW had been stocking as "greenbacks" for decades were actually Colorado River cutthroat from the Western Slope—the wrong subspecies entirely. Just in RMNP, 13 restoration projects had been stocked with the wrong fish. The planet's entire known population of actual greenbacks turned out to be a single four-mile stretch of Bear Creek on Pikes Peak, outside their native range—fish that had been isolated above a waterfall since the 1870s.
CPW has since established broodstock from Bear Creek fish and is restoring true greenbacks to historic waters. In 2022, naturally reproducing greenbacks were confirmed in Herman Gulch—the first wild reproduction of the real greenback in over a century.
What This Means for Anglers:
If you catch one in RMNP, it may be a "legacy" fish from the old stocking program or a true greenback from recent restoration—either way, handle it carefully. You're part of an ongoing conservation story with more plot twists than a novel.
A Fly Fishing Guide to Rocky Mountain National Park by Steven B. Schweitzer is the definitive resource. Schweitzer spent over 10 years hiking and fishing the park, detailing 150+ destinations with topographic maps, trail profiles, hatch charts, and local fly patterns (over 120 patterns not found in other books). The 2023 edition includes updated regulations and post-fire trail conditions. Worth the $35 investment if you're planning multiple trips. Available at Kirk's Flyshop and Amazon.
Estes Park sits at 7,500 feet; most fishing occurs between 8,000-12,000 feet. If you're arriving from sea level, take a day to acclimate before hiking to alpine lakes. Symptoms of altitude sickness include headache, fatigue, and nausea. Drink more water than you think you need.
Summer afternoons bring lightning—often by 1-2pm. Above treeline, you're the tallest object. Plan alpine lake trips to arrive at the lake by 9am and begin descent by noon. Weather changes in minutes at elevation. Always carry rain gear, even on blue-sky mornings.
Cold water isn't a problem in RMNP—warm water occasionally is. During August heat waves, shallow meadow sections can reach 65°F+.
Black bears and mountain lions live in the park. Make noise on trails, store food properly, and never approach wildlife. Elk are common in Moraine Park and Horseshoe Park—give them 75+ feet, especially during fall rut (September-October) when bulls are aggressive.
Even in August, these streams run 45-55°F. Extended immersion causes hypothermia. Wear wading boots with good traction (rubber soles, not felt) and consider a wading staff on boulder-strewn water like Glacier Creek. If you fall in, get out and warm up before continuing.
May through late June brings high, cold, silty water to freestone streams. Plan stream fishing for July-October when water clears. The tailwater below Lake Estes stays fishable during runoff.
RMNP streams are too small for dedicated gauges, but RiverReports helps plan your trip by tracking conditions on connected waters:
Primary Reference: Big Thompson River at Drake — This gauge sits below the park and reflects what's happening upstream. When it reads 100-150 CFS with stable or dropping trend, park streams are typically in good shape.
Secondary References:
How to Use:
Weekly flow updates and fishing intel.
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