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6-acre lake near Gwynedd. The lake tops out around 10 ft. Depth here is modeled from the true shoreline and max depth rather than surveyed; use it to plan, not to navigate. Below is the species-by-species picture, pulled from the same data the map uses.
Llyn y Bi maps at 6 acres behind 0.4 miles of shoreline. Its 1.1 shoreline index means few bank features; the contours below do the pattern work. Nothing on this chart breaks 15 ft, which makes the whole surface littoral: weeds, bait and ambush cover everywhere. Gwynedd claims this one. If the bite dies, Llyn Hywel is 0 mi to the west.
The spring pattern is a shallow one: brown trout in 1 to 10 ft. The depth story barely changes: 3 to 10 ft through summer, 1 to 10 ft in winter. Top water on the chart: Break off the point, a drop-off in the 5 ft range, prime in summer. Time it for after dark and early morning. Summer baits: a spoon at the thermocline or a deep stickbait (night) gets it done.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 10 ft chart-limited; documented 3 to 25 ft | dawn & dusk | Main-lake point (8 ft) | Stickbait off planer boards (shallow), Small spoon along mud lines |
| Summer | 3 to 10 ft chart-limited; documented 25 to 60 ft | night & dawn | Break off the point (5 ft) | Spoon at the thermocline, Deep stickbait (night) |
| Fall | 2 to 10 ft chart-limited; documented 5 to 30 ft | dusk & dawn | Main-lake point (8 ft) | Jerkbait over gravel, Casting spoon |
| Winter | 1 to 10 ft chart-limited; documented 5 to 35 ft | dawn | Break off the point (5 ft) | Jigging spoon, Small stickbait (slow) |
Come spring, look for european perch tight to the bank in 3 to 10 ft. Through summer count on 3 to 10 ft; the winter hold is 3 to 10 ft. Start at Deep basin. It's a deep basin holding about 9 ft of water and rates prime come fall. Prime time lands in early morning. A drop-shot micro plastics or a small crankbait (perch pattern) is the honest summer answer here.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 10 ft chart-limited; documented 3 to 12 ft | midday & dawn | Break off the point (5 ft) | Small jig + curly tail, Inline spinner #1-2 |
| Summer | 3 to 10 ft chart-limited; documented 8 to 28 ft | dawn | Deep basin (9 ft) | Drop-shot micro plastics, Small crankbait (perch pattern) |
| Fall | 3 to 10 ft chart-limited; documented 10 to 33 ft | midday | Deep basin (9 ft) | Jigging spoon (small), Drop-shot on deep flats |
| Winter | 3 to 10 ft chart-limited; documented 12 to 33 ft | midday & dawn | Deep basin (9 ft) | Tungsten jig + maggots, Small balance jig |
Early season northern pike use the shallows, holding in 2 to 8 ft. Expect a summer slide to 3 to 10 ft, then a winter hold in 3 to 10 ft. Put Break off the point first on the milk run — a drop-off near 5 ft that grades prime for fall. In summer the feeding windows fall in early morning and the evening. Tie on a bucktail or a weedless spoon over cabbage and you're in the game.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | open water | #5 inline spinner, Spoon (red/white) |
| Summer | 3 to 10 ft chart-limited; documented 8 to 20 ft | dawn & dusk | Break off the point (5 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 3 to 10 ft chart-limited; documented 6 to 18 ft | midday & dawn | Break off the point (5 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 3 to 10 ft chart-limited; documented 5 to 15 ft | midday | Main-lake point (8 ft) | Tip-ups, Large jigging spoon |
3 pieces of structure are mapped here — Deep basin, around 9 ft, is the deepest of them.
Llyn y Bi is about 10 ft (3 m) deep at its deepest point. The contours here are modeled from the water's real shape and maximum depth, so treat them as a rough guide.
Anglers target brown trout, european perch, northern pike on Llyn y Bi. This isn't a survey of the water — none is published for it — but an informed estimate from the species common to the region, narrowed by this water's depth, size and each species' range.
Deep basin is the top-rated area: a deep basin in about 9 ft of water that rates prime for european perch in fall. The interactive chart above rates every spot for each species and season.
For brown trout, the summer bite is best in after dark and early morning. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Llyn Hywel 0 mi · Llyn Dulyn 1 mi · Llyn Cwm-mynach 2 mi · Llyn Bodlyn 2 mi · Gloyw Lyn 3 mi · Llyn Cwm Bychan 3 mi · Llyn Erddyn 4 mi · Llyn Trawsfynydd 6 mi · Llyn Gwernan 7 mi · Llyn Tecwyn Isaf 7 mi · Llyn Llenyrch 7 mi · Llyn y Gadair 8 mi
See how Llyn y Bi stacks up: best northern pike lakes in United Kingdom · best european perch lakes in United Kingdom · best brown trout lakes in United Kingdom
More water nearby: Gwynedd fishing maps (35 charts). Browse all United Kingdom fishing maps. See every water on DepthScout. 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.