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894-acre Mulroy Bay. Inner saltwater fishing map with official INFOMAR survey bathymetry, measured-cell fishing spots, official fish evidence, seasonal forage guidance, access context and current-rule links. The inner trip-scale survey reach of Mulroy Bay, retaining only official survey-backed seabed cells that pass the Ireland release gates. The water tops out around 59 ft. The depth chart comes from INFOMAR (Geological Survey Ireland and Marine Institute) bathymetric survey data, so the contours are survey-derived rather than computer-modeled. What the data behind the map says about each species, season by season:
The outline encloses 894 acres, worked by 12.1 miles of shoreline. An index of 2.9 puts the bank firmly in maze territory: point after pocket after cove, every one a casting target. Roughly 52% of the water is 15 ft or less, the band where the food chain lives. Call it 3.3 mi long by 0.9 mi wide at the broadest reach. Its nearest charted neighbour, Lough Swilly - Middle, is 3 mi to the northeast.
Marine Institute spawning, nursery, observation and range layers support the principal surveyed pelagic and groundfish. IFI's national and regional sea-angling publications support additional habitat-compatible recreational targets. This is occurrence and search guidance, not equal abundance, a section-level population estimate or a promised catch. The roster may combine exact-water monitoring with habitat-filtered official regional evidence; it does not imply that every species is equally abundant throughout the mapped section.
| Species | Evidence basis | Count / date |
|---|---|---|
| Bass (European Seabass) | official species listing | — |
| Mackerel (Atlantic Mackerel) | official species listing | — |
| Herring (Atlantic Herring) | official species listing | — |
| Whiting (Whiting) | official species listing | — |
| Flounder (European Flounder) | official species listing | — |
| Plaice (European Plaice) | official species listing | — |
| Sole (Common Sole) | official species listing | — |
| Thornback ray (Thornback Ray) | official species listing | — |
| Thick-lipped grey mullet (Thick-lipped Grey Mullet) | official species listing | — |
| Garfish (Garfish) | official species listing | — |
| Sea trout (Sea Trout) | official species listing | — |
Official species-evidence source.
Come spring, look for european seabass tight to the bank in 3 to 25 ft. Expect a summer slide to 2 to 30 ft, then a winter hold in 10 to 55 ft. Start at INFOMAR measured current seam. It's a current seam holding about 27 ft of water and rates prime come summer. Prime time lands in early morning and the evening. A surface lure or a paddle-tail soft plastic is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 25 ft | dawn & dusk | INFOMAR measured current seam (27 ft) | Paddle-tail soft plastic, Shallow minnow plug |
| Summer | 2 to 30 ft | dawn & dusk | INFOMAR measured current seam (27 ft) | Surface lure, Paddle-tail soft plastic |
| Fall | 4 to 40 ft | dawn & dusk | INFOMAR measured current seam (27 ft) | Slim metal lure, Minnow plug |
| Winter | 10 to 55 ft | midday | INFOMAR measured channel edge (32 ft) | Slow soft-plastic shad, Suspending minnow |
Start shallow in spring: atlantic mackerel sit in 5 to 45 ft that time of year. Summer pushes them deeper, 11 to 59 ft, and winter fish settle into 15 to 59 ft. The spot to know is Deepest basin, a deep basin in about 59 ft of water that rates prime for atlantic mackerel in summer. Warm-month bites cluster around early morning and the evening. Throw a feather rig or a small vertical jig until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 45 ft | dawn & dusk | INFOMAR measured current seam (27 ft) | Mackerel feather rig, Small silver jig |
| Summer | 11 to 59 ft | dawn & dusk | Deepest basin (59 ft) | Feather rig, Small vertical jig |
| Fall | 9 to 59 ft | dawn & dusk | INFOMAR measured current seam (27 ft) | Compact silver jig, Sparse feather rig |
| Winter | 15 to 59 ft | midday | Deepest basin (59 ft) | Small deep jig |
Come spring, look for atlantic herring tight to the bank in 5 to 25 ft. Expect a summer slide to 15 to 50 ft, then a winter hold in 18 to 59 ft. Start at Deepest basin. It's a deep basin holding about 59 ft of water and rates prime come winter. Prime time lands in early morning and the evening. A herring feather rig or a small silver jig is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 25 ft | dawn & dusk | INFOMAR measured current seam (27 ft) | Small herring feather rig, Micro jig rig |
| Summer | 15 to 50 ft | dawn & dusk | Deepest basin (59 ft) | Herring feather rig, Small silver jig |
| Fall | 10 to 40 ft | dawn & dusk | INFOMAR measured current seam (27 ft) | Small feather rig, Compact silver spoon |
| Winter | 18 to 59 ft | midday | Deepest basin (59 ft) | Small silver jig, Sparse feather rig |
Spring whiting on Mulroy Bay - Inner hold shallow, usually 15 to 55 ft. By summer they slide out to 17 to 59 ft, and by winter most fish are in 13 to 59 ft. The chart's best answer is INFOMAR measured channel edge — channel edge, 32 ft, prime for spring. Prime time lands in early morning. The summer box starts with a small vertical jig.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 15 to 55 ft | dawn & dusk | INFOMAR measured channel edge (32 ft) | Small silver jig, Two-hook feather rig |
| Summer | 17 to 59 ft | dawn | Deepest basin (59 ft) | Small vertical jig |
| Fall | 10 to 59 ft | dusk | INFOMAR measured channel edge (32 ft) | Small silver jig, Sparse feather rig |
| Winter | 13 to 59 ft | dusk | Deepest basin (59 ft) | Compact vertical jig |
Start shallow in spring: european flounder sit in 5 to 25 ft that time of year. Summer pushes them deeper, 6 to 35 ft, and winter fish settle into 15 to 50 ft. The spot to know is INFOMAR measured flat, a feeding flat in about 8 ft of water that rates prime for european flounder in spring. Warm-month bites cluster around early morning and the evening. Throw a bottom jig with spinner blade until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 25 ft | dusk | INFOMAR measured flat (8 ft) | Small bucktail dragged on bottom |
| Summer | 6 to 35 ft | dawn & dusk | INFOMAR measured flat (8 ft) | Bottom jig with spinner blade |
| Fall | 8 to 40 ft | dusk | Sharp break (11 ft) | Compact bottom jig |
| Winter | 15 to 50 ft | midday | Sharp break (11 ft) | Small bottom jig |
Spring european plaice on Mulroy Bay - Inner hold shallow, usually 8 to 35 ft. By summer they slide out to 6 to 40 ft, and by winter most fish are in 18 to 59 ft. The chart's best answer is INFOMAR measured flat — feeding flat, 8 ft, prime for spring. Prime time lands in early morning and the evening. The summer box starts with a light spooned bottom rig or a beaded trace.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 8 to 35 ft | dusk | INFOMAR measured flat (8 ft) | Beaded flowing trace |
| Summer | 6 to 40 ft | dawn & dusk | INFOMAR measured flat (8 ft) | Light spooned bottom rig, Beaded trace |
| Fall | 10 to 50 ft | dusk | INFOMAR measured channel edge (32 ft) | Beaded bottom trace |
| Winter | 18 to 59 ft | midday | Deepest basin (59 ft) |
Mulroy Bay - Inner also holds common sole (3 to 30 ft in summer), thornback ray (9 to 59 ft in summer), thick-lipped grey mullet (1 to 18 ft in summer), garfish (2 to 20 ft in summer), sea trout (15 to 50 ft in summer). Pick any of them on the map above for rated spots and bait picks.
Mulroy Bay - Inner carries 7 mapped structure features, topping out (or rather bottoming out) at Deepest basin, about 59 ft down.
The complete Marine Institute Fishing Ports layer returned no port point inside this operational section. DepthScout does not substitute a nearby road, beach or community slipway as verified public fishing access; confirm legal access, parking, tides and local restrictions before visiting.
Private land and private launches need the owner's permission — please ask first.
Season dates, license requirements, and size and bag limits for Ireland waters are set by the Inland Fisheries Ireland (current sea-angling regulations) — and special regulations can apply to Mulroy Bay - Inner specifically, so confirm the current rules before you fish. Check the current national and water-specific rules before every trip, including bass measures, the 2026 recreational pollack controls, salmon and sea-trout licences and river-specific status, protected areas, harbour directions, private land and local signs. A mapped fishing port or measured seabed feature is not permission to fish, park, launch or enter a working harbour.
Check the official Ireland fishing regulations →
Department of Climate, Energy and the Environment (2026 salmon and sea-trout status) →
Check special-area and water-specific rules →
Check official shore-access information →
Mulroy Bay - Inner is about 59 ft (18 m) deep at its deepest point. The depth chart comes from INFOMAR (Geological Survey Ireland and Marine Institute) bathymetric survey data, so the contours are survey-derived rather than computer-modeled.
Official coastal monitoring from Marine Institute and Inland Fisheries Ireland informs the european seabass, atlantic mackerel, atlantic herring, whiting, european flounder, european plaice, common sole, thornback ray, thick-lipped grey mullet, garfish, sea trout roster for Mulroy Bay - Inner. The mixed roster combines exact-water records where available with habitat-filtered regional evidence; not every species is documented at this exact water, and it is not a promise of equal abundance or a catch on a particular trip.
INFOMAR measured current seam is the top-rated area: a current seam in about 27 ft of water that rates prime for european seabass in summer. Every other rated spot, per species and season, is on the map above.
For european seabass, 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 Mulroy Bay - Inner is regulated by the Inland Fisheries Ireland (current sea-angling regulations). Check the official Ireland regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Lough Swilly - Middle 3 mi · Lough Foyle - Inner 6 mi, IRL/UK · Mulroy Bay - Outer 11 mi · Lough Foyle - Middle 14 mi, IRL/UK · Lough Swilly - Outer 17 mi · Sheephaven Bay - East 20 mi · Lough Foyle - Outer 22 mi, IRL/UK · Sheephaven Bay - West 34 mi · The Rosses and Gweedore Bay - Outer Islands 40 mi · Gweebarra Bay - Outer 44 mi · Donegal Bay - Central East 46 mi · Donegal Bay - Central West North 48 mi
See how Mulroy Bay - Inner stacks up: best sea trout lakes in Ireland · best atlantic herring lakes in Ireland · best european flounder lakes in Ireland · best garfish lakes in Ireland
Browse all Ireland fishing maps. See every water on DepthScout. Bathymetry credit: INFOMAR (Geological Survey Ireland and Marine Institute) INFOMAR All Survey bathymetry mosaic (Source-survey vertical references retained in the INFOMAR All Survey mosaic; 100% measured, 0% source-interpolated). 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.