Wyoming ·
Lamar River Fly Fishing Report - April 4/12/2026
LAMAR RIVER FLY FISHING REPORT
Yellowstone National Park — Lamar Valley & Upper Yellowstone drainage
Report Date: April 12, 2026 | Next Update: April 19, 2026
Regulations & Access (REQUIRED)
Status: OPEN — Lamar River fishing is allowed under Yellowstone National Park regulations. Anglers must follow current NPS rules (permits, bait restrictions, and area-specific rules). Many park trout waters require artificial flies and lures only and use of barbless hooks; special rules apply for native cutthroat protection in certain reaches. Always confirm the current, official regulations and seasonal closures before you fish:
Official NPS Yellowstone fishing information: nps.gov/yell/planyourvisit/fishing.htm
Official NPS Yellowstone fishing information: nps.gov/yell/planyourvisit/fishing.htm
Current River Conditions
Early spring conditions — cold water and rising flows from snowmelt. Focus on sub-surface presentations and slow streamer work in deeper runs.
Flows & Clarity
Flow: Rising with spring runoff (expect higher, faster currents in afternoon)
Water Clarity: Mostly stained to off-color in run/riffle sections; pockets of clearer water in sheltered tailouts and undercut banks
Flow: Rising with spring runoff (expect higher, faster currents in afternoon)
Water Clarity: Mostly stained to off-color in run/riffle sections; pockets of clearer water in sheltered tailouts and undercut banks
Water Temperature
Current: ~34–42°F (1–6°C)
Daily Trend: Cold mornings; slight warming midday but water remains cold—fish metabolism is slow
Current: ~34–42°F (1–6°C)
Daily Trend: Cold mornings; slight warming midday but water remains cold—fish metabolism is slow
Weather & Access
Forecast: Cool; chance of snow or rain at higher elevations; daytime highs in the 30s–40s°F
Road/Access: Some park roads/lot access may still have snow—check NPS road status before travel
Forecast: Cool; chance of snow or rain at higher elevations; daytime highs in the 30s–40s°F
Road/Access: Some park roads/lot access may still have snow—check NPS road status before travel
Target Species
Yellowstone cutthroat, brook, brown trout — fish deep and slow; resident trout are concentrated in holding water where currents moderate
Yellowstone cutthroat, brook, brown trout — fish deep and slow; resident trout are concentrated in holding water where currents moderate
What’s Hatchin’ (April 12)
| Insect | Size | Activity Level | Prime Time |
|---|---|---|---|
| Midges (Chironomids) | #18–24 | Heavy — primary food source right now | All day (esp. low light / overcast) |
| Blue-winged Olives (Baetis) | #18–22 | Light–Moderate — sporadic emergences and rises on warm middays | Late morning to early afternoon, best on calm, bright patches |
| Caddis | #16–20 | Minor activity — evenings only in quieter pockets | Evening |
| Stoneflies / Salmonflies | — | Not expected (season too early for major stonefly/salmonfly hatches) | — |
Cold‑Water Strategy (focus for April)
Primary game plan: deep nymphing and midge presentations in the mornings and low light; slow, deliberate streamer work in deeper runs/undercuts during midday and when water pockets clear. Dry-fly opportunities are limited — concentrate on emergers (BWO) when rises appear.
Recommended Flies — Seasonally appropriate
Below are proven patterns chosen for early‑spring Lamar River conditions (cold water, midge/BWO activity, and resident trout holding deep). URLs link to pattern references for ordering/visuals. Prioritization considered typical effectiveness for April; Google-sheet ranks were used as a secondary guide where appropriate.
Nymphs (deep, tungsten & jig styles — 4 recommended)
- Egan's Thread Frenchie Jig — Olive (tungsten/jig — great as an anchor/point fly)
- Roza's Black Perdigon — Barbless (slick, fast-sinking perdigon for deep runs)
- Pheasant Tail (Tungsten) (classic mayfly nymph in small sizes for BWO nymphing)
- Perdigon Nymph — Black (dense profile and fast sink for tight, deep drifts)
Midges / Chironomids (critical in April — 4 recommended)
- Black Zebra Midge (TBH) — small, slim jig; excellent index or dropper fly
- Top Secret Midge — versatile midge for dead-drift presentations
- Jig Zebra Midge — Black — jig style for tight, subtle depth control
- Redneck Midge — very small sizes for selective fish in slick water
BWO / Emergers & Small Dries (4 recommended)
- Parachute — Blue Wing Olive — go-to for sporadic BWO activity
- Antonio's Adult BWO — excellent adult/BWO imitation
- Barr's Flashback Emerger — BWO — use as dropper/emergent when fish sip on emergers
- Bead Head Barr Emerger — BWO — tungsten emerger for precise depth and longer drifts
Streamers & Larger Profiles (slow retrieves, 4 recommended)
- Coffey's CH Sparkle Minnow — Sculpin — sculpin profile for deeper runs and tailouts
- Sculpzilla — Olive — articulated/large sculpin imitation for slow strips
- Near Nuff Sculpin — Olive — sculpin/baitfish profile for probing structure
- Galloup's Slick Willy — Whitefish — baitfish streamer for deeper pools
Soft-hackles & Soft/Hatch‑style Nymphs (4 recommended)
- Soft Hackle Pheasant Tail Jig — Barbless — swing or slow-drift as an emerger/soft-hackle
- Duracell Bomb — Pheasant Tail — soft profile for sighter presentations
- Duracell Bomb — Hare's Ear — soft-hackle style with nymph weight
- Soft Hackle — Hare's Ear (Barbless) — classic soft-hackle for swinging or dead-drifted presentations
Tactics & Tips — April (Cold-water focus)
- Deep Nymphing (primary): Euro nymphing or indicator rigs. Use tungsten beadheads/perdigons as your point fly to get to fish-holding depths quickly. Start with 1–2 small, heavy nymphs (sizes 16–20 for BWO/midge; size 14–16 for larger stone/may nymph imitations when present). Keep leaders short and sensitive for bite detection.
- Rig suggestions: 6–9' fluorocarbon leader with a 1–2' tippet bite zone; for indicator rigs, use a longer leader (10–12') with strike indicator and 12–18" between indicator and point fly. For Euro, use a 10–12' leader tapered to 0.18–0.15mm, with 1–2 tungsten nymphs.
- Midge setups: small jig or zebra midge on the point, tandem droppers of size #18–24; keep flies low and slow in seams and pockets. Fish midges under a small indicator or tight inline nymph rigs. In the low light or overcast, fish very small, dark midges close to the surface film.
- Streamer approach: cold-water strip — long, slow strips with pauses. Target deep seams, undercut banks, and structure when the sun warms slightly. Use olive/brown sculpin patterns on sink-tip or heavy leader (6–10 ft sink-tip) and strip with 2–4 slow pulls, then pause 5–10 seconds. Trout are lethargic: slower action often outperforms frantic stripping.
- Dry/Emerger windows: when you see rising trout or a mid‑day BWO hatch, switch to emergers and small parachute BWO patterns. Cast upstream and dead-drift; keep drag off and present at mid-column depths.
- Tippet: 4X–6X baseline for nymphs/emers — drop to 5X–7X for the smallest midges. For streamers use 3X–5X heavy leader (30–10 lb) to turn over bigger flies and to absorb runs.
- Rig suggestions: 6–9' fluorocarbon leader with a 1–2' tippet bite zone; for indicator rigs, use a longer leader (10–12') with strike indicator and 12–18" between indicator and point fly. For Euro, use a 10–12' leader tapered to 0.18–0.15mm, with 1–2 tungsten nymphs.
- Midge setups: small jig or zebra midge on the point, tandem droppers of size #18–24; keep flies low and slow in seams and pockets. Fish midges under a small indicator or tight inline nymph rigs. In the low light or overcast, fish very small, dark midges close to the surface film.
- Streamer approach: cold-water strip — long, slow strips with pauses. Target deep seams, undercut banks, and structure when the sun warms slightly. Use olive/brown sculpin patterns on sink-tip or heavy leader (6–10 ft sink-tip) and strip with 2–4 slow pulls, then pause 5–10 seconds. Trout are lethargic: slower action often outperforms frantic stripping.
- Dry/Emerger windows: when you see rising trout or a mid‑day BWO hatch, switch to emergers and small parachute BWO patterns. Cast upstream and dead-drift; keep drag off and present at mid-column depths.
- Tippet: 4X–6X baseline for nymphs/emers — drop to 5X–7X for the smallest midges. For streamers use 3X–5X heavy leader (30–10 lb) to turn over bigger flies and to absorb runs.
Where to Fish / Key Water
| Zone | Why it Works | How to Fish It |
|---|---|---|
| Deep tailouts & pool heads | Holds trout moving between runs; deeper water warms slightly midday | Slow streamer sweeps; deep nymphs fished tight to the seam |
| Slow runs & undercut banks | Fish hold out of main current; prime for strip‑pause streamer takes | Slow, deliberate streamer retrieves; twitching sculpin patterns |
| Slicks & inside seams | Concentrated feeding lanes for trout sipping midges & BWOs | Euro nymph close to the seam; midge dropper setups with small indicators |
| Shallow riffles (early morning) | Good for indicator nymphing and sighting fish when water clears briefly | Two‑fly nymph rigs (dropper anchored with tungsten point fly) |
Quick Gear Checklist
Rods & Lines
9' 4–6 wt for nymph/dry work; 7–8 wt or 6–7 wt with sink-tip for streamers
9' 4–6 wt for nymph/dry work; 7–8 wt or 6–7 wt with sink-tip for streamers
Leaders & Tippet
Fluorocarbon 6–12' tapered leaders; tippets 4X–7X; 40–10 lb shock tippet for streamers
Fluorocarbon 6–12' tapered leaders; tippets 4X–7X; 40–10 lb shock tippet for streamers
Essential Flies
See recommended lists above — pack a variety of beadhead perdigons, zebra midges and olive sculpin streamers
See recommended lists above — pack a variety of beadhead perdigons, zebra midges and olive sculpin streamers
Safety
Cold-water protection: neoprene waders/bibs, layered clothing, wading staff. Tell someone your plan.
Cold-water protection: neoprene waders/bibs, layered clothing, wading staff. Tell someone your plan.
Note: This is a seasonal, cold‑water report for April conditions. Hatch activity and water levels can change quickly in spring; adjust presentations for visibility and current. Respect park rules and posted closures — and double-check the NPS fishing page for any last‑minute regulation updates.
