Summary
Sea Mills Harbour sits on the tidal River Avon in Bristol, where the River Trym meets the estuary. It’s a classic inner-estuary mark for flounder, schoolie bass, mullet and eels, with fierce tides and big spring ranges. If you time it right around the slacker water, it can be very rewarding without needing long casts.
Location and Access
Access is straightforward from the A4 Portway or via Sea Mills train station on the Severn Beach Line. The harbour area is compact, with options to fish from the outer wall, adjacent railings and firm foreshore areas at lower water.
- Driving: Reach Sea Mills from the A4 Portway; local streets signposted for Sea Mills/Sea Mills Station. The harbour is a short detour from the Portway.
- Parking: On-street around Sea Mills Square/Sea Mills Lane (BS9 area). There is also a small station car park near Sea Mills station; be considerate of residents and signage.
- Public transport: Sea Mills station is about a 5–10 minute walk to the harbour. Regular trains on the Severn Beach Line from Bristol Temple Meads/Clifton Down.
- Walk and terrain: Mostly flat tarmac paths with some cobbles and a sloped slipway. The outer wall is firm but can be slimy; foreshore becomes soft mud away from the main channel – keep to obvious, firmed surfaces only.
Seasons
This is a brackish, fast-flowing estuary mark with a seasonal mix. Expect turbidity, huge tides and fish that move with the flow.
- Spring (Mar–May):
- Schoolie bass
- Flounder
- Thick‑lipped grey mullet appearing toward late spring
- Summer (Jun–Aug):
- Thick‑lipped and thin‑lipped grey mullet
- Schoolie bass (odd better fish among them)
- European eel (must be released – see regulations)
- Autumn (Sep–Nov):
- Bass (often best numbers)
- Flounder
- Mullet until the first real cold snaps
- Winter (Dec–Feb):
- Flounder (peak months)
- Occasional codling further down-channel, but at Sea Mills it’s mainly flounder sport
- Year-round visitors (occasional):
- Whiting on very cold, salty pushes (less common this far inland)
- Estuary-feeding silver eels in milder spells (release only)
Methods
Short-to-medium range fishing is the norm, working the near-channel and eddies as the tide eases. Present baits tidily and keep rigs streamlined to cope with flow and debris.
- Bottom fishing:
- 2-hook flapper or single running ledger for flounder and bass; keep traces short in the run, slightly longer near slack water.
- Breakout (grip) leads on the flood/ebb; plain leads near slack to let baits waft.
- Hooks: size 4–2 for flounder and eels; size 2–1/0 for bass.
- Baits: ragworm and lugworm are prime; peeler crab (spring/summer) for bass; maddies for flounder; mackerel or bluey strip for eels/bass; mussel can score after fresh.
- Mullet tactics:
- Light float or freelined bread flake; size 8–12 fine-wire hooks; chum with mashed bread sparingly and let fish settle.
- Thin‑lips will also take small artificial “maddies” on a float/spinner rig in clearer neap conditions.
- LRF/soft plastics:
- 2–3 inch paddletails or worms in drab estuary colours fished on light jigheads during the last hour of flood/first of ebb can pick up schoolie bass in slack pockets.
- Timing:
- Focus your main effort on the last 2 hours of flood, high-water slack, and first hour of ebb when presentation is possible and bites register.
Tides and Conditions
The Bristol Channel’s range is immense here; Sea Mills sees brutal flow on springs and a short but productive window around slack water. Plan around the state of tide first, then wind and clarity.
- Best tide states:
- Last 2 hours of the flood and the turn of the tide are prime; first hour of ebb also good before debris builds.
- Springs: good for flounder movement but powerful flow – fish nearer the wall with streamlined rigs.
- Neaps: better water clarity and control for mullet and LRF.
- Time of day:
- Dawn and dusk are consistent for bass and mullet in summer; winter flounder bite well in the daytime around the top of the tide.
- Water and weather:
- After heavy rain, freshwater pushes and chocolate-coloured water can slow mullet sport but suit flounder/eels.
- Moderate westerlies can add surge and debris; calmer periods after a couple of dry days favour mullet.
- Tide references:
- Use Avonmouth tide times as your reference; Sea Mills turns shortly after Avonmouth. Arrive early to set up before the flow eases.
Safety
This is a fast, tidal river with mud flats and slippery structures. A cautious approach and sensible footwear are essential.
- Tidal hazards:
- Very strong currents on the flood/ebb; do not wade and do not step onto exposed mud – it can be soft and sinky.
- Keep clear of the edge and ladders; walls and cobbles get slick with weed and silt.
- Structures and activity:
- Do not fish from pontoons or obstruct the slipway/boat access when paddlesports or small craft are launching.
- Expect floating debris on springs; keep rod tips high and use rod rests to avoid snagging weed.
- Personal safety:
- A waist or auto-inflating lifejacket is strongly recommended, especially when fishing the wall at higher stages.
- Headtorch, spare light and a throw line in the bag are good practice if fishing into dusk.
- Accessibility:
- Short level approach with some uneven cobbles; suitable for most, but not ideal for wheelchairs due to surfaces/edges.
- Local restrictions:
- Observe any harbour signage; some areas may be locally marked as no fishing or no access when events/maintenance are underway.
Facilities
Facilities are limited at the harbour itself, but you’re in a residential suburb with essentials a short walk away.
- Toilets: None on-site; use local cafés/shops around Sea Mills Square during opening hours.
- Food and drink: Small shops and cafés in Sea Mills; more options along the A4 toward Shirehampton/Clifton.
- Tackle and bait:
- Bristol Angling Centre (city side) and Premier Angling (Keynsham) are the main full-range stores; phone ahead for fresh worm/crab.
- Phone signal: Generally good around the Portway/Sea Mills.
- Public transport: Sea Mills station on the Severn Beach Line is close; buses run along the Portway.
Tips
The mark rewards tide timing, neat rigs and not overcasting. Treat it like an estuary river swim rather than an open shore.
- You rarely need to whack it out; most bites come from the near-side channel and eddies 10–30 yards out.
- Keep bait small and fresh. A single decent ragworm or a crab knuckle outfishes big cocktails in the flow.
- Chum lightly for mullet and let them settle; too much bread brings them up but scatters the shoal.
- Use a long-handled landing net from the wall; the drop varies with tide and fish are lost at the top on short nets.
- Carry spare leads and a simple trace wallet; the Avon loves eating gear on springs.
- After a freshet, try mussel or worm tipped with fish strip for a flounder or accidental bass.
- Weed build-up often peaks mid-ebb on big springs; either fish the slack or step up to stronger snoods and check lines frequently.
Regulations
Regulations can change; always check the latest from the MMO, your local IFCA and the Environment Agency before you go.
- Access/fishing:
- Sea Mills is an active community harbour; do not fish from pontoons and do not obstruct the slipway. Obey any posted harbour notices.
- Bass rules:
- Recreational bass measures (bag limits, open seasons, 42 cm minimum size) are updated periodically. Check current rules for ICES area 7 (Bristol Channel) on the MMO website before retaining any bass.
- European eel:
- It is illegal to retain European eel (Anguilla anguilla). Release all eels unharmed.
- Salmonids/coarse fish licences:
- No rod licence is required to fish for sea species in tidal waters, but you do need an Environment Agency licence if intentionally fishing for salmon, trout or freshwater coarse species in the estuary.
- Bait collection and protected sites:
- Parts of the Avon/Severn estuary system are designated (SSSI/SPA/Ramsar). Avoid bait digging on protected mudflats and only collect bait where it is permitted.
- General good practice:
- Take litter and line home, use barbless or crushed barbs for mullet if possible, and respect other water users and residents.