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2,342-acre lake in Nipissing District, Ontario. The lake tops out around 120 ft. The depth data here comes from the Ontario MNRF survey of 1974, a decades-old survey (a transect sounding survey). Here is how the season plays out for each species, straight from the data behind the map.
Diamond Lake maps at 2,353 acres behind 37.9 miles of shoreline, broken up by 25 islands. That shoreline is heavily fingered (development index 5.6) — bays, points and pockets everywhere, which multiplies the fishable edge. Littoral water — the productive band under ~15 ft — makes up 41% of this chart. Tip to tip the water measures near 6.3 mi with a 4-mi widest point. Nipissing District claims this one. Bob Lake sits 3 mi south — the closest neighbouring chart.
Spring brook trout on Diamond Lake hold shallow, usually 2 to 15 ft. They move out to 10 to 30 ft in summer and finish the year down in 3 to 20 ft. Put Break off the point first on the milk run — a drop-off near 23 ft that grades prime for summer. The feeding windows run early morning and the evening. The summer box starts with a small spoon fished deep or a trolled lake-clear wobbler + worm.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 15 ft | dawn & dusk | Main-lake point (12 ft) | Small inline spinner (gold), Tiny spoon |
| Summer | 10 to 30 ft | dawn & dusk | Break off the point (23 ft) | Small spoon fished deep, Trolled lake-clear wobbler + worm |
| Fall | 2 to 15 ft | midday & dawn | Main-lake point (12 ft) | Small spoon (orange), Spinner |
| Winter | 3 to 20 ft | dawn | Shallow bay flat (8 ft) | Small jigging spoon, Tungsten jig + plastic |
Come spring, look for lake trout tight to the bank in 10 to 40 ft. They move out to 50 to 120 ft in summer and finish the year down in 20 to 80 ft. If you only fish one area, make it Deep basin: a deep basin around 118 ft that scores prime in summer. Best bite is early morning. A white tube jig (deep) or a magnum spoon on downrigger is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Main-lake point (12 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 50 to 120 ft | dawn | Deep basin (118 ft) | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 10 to 50 ft | dusk & dawn | Main-lake point (12 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 20 to 80 ft | dawn | Break off the point (23 ft) | White tube jig, Airplane jig |
The spring pattern is a shallow one: lake whitefish in 15 to 45 ft. Midsummer fish sit out in 40 to 90 ft before dropping to 25 to 70 ft for winter. The spot to know is Break off the point, a drop-off in about 23 ft of water that rates prime for lake whitefish in spring. Plan around early morning in the warm months. Summer baits: a blade bait vertical or a small jigging spoon gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 15 to 45 ft | midday & dawn | Break off the point (23 ft) | Small jig + waxworm, Blade bait (small) |
| Summer | 40 to 90 ft | dawn | Deep basin (118 ft) | Blade bait vertical, Small jigging spoon |
| Fall | 8 to 30 ft | dusk | Break off the point (23 ft) | Small spoon (gold), Jig + plastic larva |
| Winter | 25 to 70 ft | midday & dawn | Break off the point (23 ft) | Jigging spoon + bead chain, Tungsten jig + waxie |
The spring pattern is a shallow one: cisco (lake herring) in 10 to 40 ft. Midsummer fish sit out in 40 to 80 ft before dropping to 20 to 60 ft for winter. The spot to know is Break off the point, a drop-off in about 23 ft of water that rates prime for cisco (lake herring) in winter. Plan around early morning in the warm months. Summer baits: a vertical flutter spoon (small) or a drop-shot micro plastic gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Break off the point (23 ft) | Small silver spoon, Tiny swim jig (white) |
| Summer | 40 to 80 ft | dawn | Deep basin (118 ft) | Vertical flutter spoon (small), Drop-shot micro plastic |
| Fall | 5 to 25 ft | dusk & dawn | Break off the point (23 ft) | Small casting spoon, Inline spinner (silver) |
| Winter | 20 to 60 ft | dawn | Break off the point (23 ft) | Small jigging spoon (glow/silver), Tungsten jig + minnow head |
Spring puts walleye in skinny water — 4 to 15 ft is the zone. As the season builds they drop to 15 to 35 ft, wintering in 20 to 40 ft. Fall walleye concentrate at Break off the point, a prime-rated drop-off around 23 ft. Warm-month bites cluster around the evening and early morning. A crawler harness on bottom bouncer or a deep crankbait (trolled) covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 4 to 15 ft | dusk & dawn | Main-lake point (12 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 15 to 35 ft | dusk & dawn | Break off the point (23 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 12 to 40 ft | dusk & night | Break off the point (23 ft) | Jigging rap, Jig + big minnow |
| Winter | 20 to 40 ft | dusk & dawn | Break off the point (23 ft) | Jigging spoon + minnow head, Rattle bait |
Start shallow in spring: yellow perch sit in 3 to 12 ft that time of year. Summer pushes them deeper, 10 to 30 ft, and winter fish settle into 15 to 35 ft. The spot to know is Shallow bay flat, a weed flat in about 8 ft of water that rates prime for yellow perch in spring. Warm-month bites cluster around early morning. Throw a drop-shot micro plastics or a small spoon tipped with worm until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (8 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Break off the point (23 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Break off the point (23 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Break off the point (23 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Diamond Lake also holds northern pike (8 to 20 ft in summer), smallmouth bass (10 to 30 ft in summer). Pick any of them on the map above for rated spots and bait picks.
8 pieces of structure are mapped here — Deep basin, around 118 ft, is the deepest of them.
Season dates, license requirements, and size and bag limits for Ontario waters are set by the Ontario fishing regulations (FMZ summary) — and special regulations can apply to Diamond Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Diamond Lake is about 120 ft (37 m) deep at its deepest point. The depth data here comes from the Ontario MNRF survey of 1974, a decades-old survey (a transect sounding survey).
Anglers target brook trout, lake trout, lake whitefish, cisco (lake herring), walleye, yellow perch, northern pike, smallmouth bass on Diamond Lake.
Deep basin is the top-rated area: a deep basin in about 118 ft of water that rates prime for lake trout in summer. Every other rated spot, per species and season, is on the map above.
For brook trout, the summer bite is best in early morning and the evening. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Fishing on Diamond Lake is regulated by the Ontario fishing regulations (FMZ summary). Check the official Ontario regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Bob Lake 3 mi · Stars L. 4 mi · Walsh Lake 4 mi · Sladen Lake 40 4 mi · Willow Island Lake 4 mi · Medina L. 932 5 mi · Sirdevan Lake 5 mi · Wakimika Lake 6 mi · Aston Lake 6 mi · Barmac Lake 8 mi · Chris Willis Lake 8 mi · Lady Evelyn L. 8 mi
See how Diamond Lake stacks up: best smallmouth bass lakes in Ontario · best walleye lakes in Ontario · best northern pike lakes in Ontario · best yellow perch lakes in Ontario
More water nearby: Nipissing District fishing maps (683 charts). Browse all Ontario fishing maps or see every water on DepthScout. Bathymetry credit: state fisheries survey programs. How we build these maps. Fish here with a sonar unit that logs? Send us your depth data and we'll improve this chart, credited to you. For fishing guidance only, never navigation.