- Water quality Excellent sampled 15 Sep 2026
- Sea temp 13.5 °C surface, modelled
- Waves 0.5 m period 4 s · N
- Wind 11 mph from NE · gust 18
- Next tide High 04:23 today · 2.6 m
Portmuck is a coastal beach on the Antrim Coast coast, in the Mid and East Antrim Borough Council.
Conditions now
Air
10°C
Partly cloudy
Swell
0.4m
period 3 s · N
Rain
0mm
last 48 hours
Water quality
A designated bathing water: DAERA samples it weekly through the bathing season (1 June–15 September).
Latest sample 15 Sep 2026: Excellent — E. coli 31, intestinal enterococci 40 CFU/100 ml
Sample history (40 shown)
| Date | E. coli | Ent. | Rating | Algae |
|---|---|---|---|---|
| 15 Sep 2026 | 31 | 40 | Excellent | — |
| 10 Sep 2026 | 10 | 10 | Excellent | — |
| 2 Sep 2026 | 10 | 10 | Excellent | — |
| 26 Aug 2026 | 29 | 10 | Excellent | — |
| 21 Aug 2026 | 10 | 10 | Excellent | — |
| 13 Aug 2026 | 10 | 10 | Excellent | — |
| 10 Aug 2026 | 10 | 10 | Excellent | — |
| 5 Aug 2026 | 10 | 10 | Excellent | — |
| 28 Jul 2026 | 12 | 10 | Excellent | — |
| 24 Jul 2026 | 10 | 10 | Excellent | — |
| 20 Jul 2026 | 10 | 10 | Excellent | — |
| 17 Jul 2026 | 15 | 10 | Excellent | — |
| 8 Jul 2026 | 10 | 10 | Excellent | — |
| 2 Jul 2026 | 70 | 29 | Excellent | — |
| 22 Jun 2026 | 26 | 49 | Excellent | — |
| 16 Jun 2026 | 10 | 10 | Excellent | — |
| 9 Jun 2026 | 21 | 10 | Excellent | — |
| 4 Jun 2026 | 470 | 70 | Good | — |
| 1 Jun 2026 | 55 | 40 | Excellent | — |
| 26 May 2026 | 200 | 40 | Excellent | — |
| 8 Sep 2025 | 10 | 10 | Excellent | — |
| 2 Sep 2025 | 10 | 10 | Excellent | — |
| 28 Aug 2025 | 41 | 50 | Excellent | — |
| 20 Aug 2025 | 10 | 10 | Excellent | — |
| 15 Aug 2025 | 10 | 10 | Excellent | — |
| 11 Aug 2025 | 10 | 10 | Excellent | — |
| 8 Aug 2025 | 10 | 19 | Excellent | — |
| 30 Jul 2025 | 10 | 10 | Excellent | — |
| 29 Jul 2025 | 1600 | 200 | Advice against bathing | — |
| 24 Jul 2025 | 26 | 10 | Excellent | — |
| 16 Jul 2025 | 110 | 10 | Excellent | — |
| 8 Jul 2025 | 10 | 10 | Excellent | — |
| 3 Jul 2025 | 10 | 10 | Excellent | — |
| 30 Jun 2025 | 10 | 10 | Excellent | — |
| 24 Jun 2025 | 190 | 100 | Excellent | — |
| 20 Jun 2025 | 10 | 10 | Excellent | — |
| 18 Jun 2025 | 10 | 10 | Excellent | — |
| 12 Jun 2025 | 10 | 10 | Excellent | — |
| 6 Jun 2025 | 10 | 10 | Excellent | — |
| 2 Jun 2025 | 10 | 10 | Excellent | — |
Weekly lab samples, not real-time. Avoid bathing for 48 h after heavy rain. Bathing Water Profile (PDF).
Sewage & storm overflows
2 NI Water storm overflows within 1.2 mi.
Measured in 20257 spills<1 h · 1 in the bathing season · 1 of 2 monitored
| Overflow | Distance | Classification | Modelled spills/yr | Measured 2025 |
|---|---|---|---|---|
| Mullaghboy Islandmagee FA CSO | 0.7 mi | To be Determined | — | — |
| Ros Na Righ WwPS → Larne Lough |
1.1 mi | To be Determined | — | 7 spills 1 in season · <1 h |
How these are counted
“Modelled” is NI Water's hydraulic-model prediction of spills per year. “Measured” is from NI Water's event duration monitors, counted with the industry 12/24 method (discharges within the same 12- or 24-hour block count as one spill); the bathing-season figure (1 Jun–15 Sep) is our count from NI Water's published discharge log. An overflow with no monitor isn't known to be dry. Classification is NI Water's own.
Nearest wastewater treatment works: Mullaghboy Islandmagee WwTW (0.7 mi → North Channel) · Ferris Bay 50 ST (2.0 mi → Larne Lough).
Amenities & features
Parking
2
Toilets
1
Picnic tables
7
Boating — nearest harbours & marinas
- Islandmagee 70 yd
- Ballylumford 2.5 mi
- Larne 2.8 mi
2 more further away
- Whitehead 6.4 mi
- Unknown 7.3 mi
Wildlife & designations
This beach lies in or within 0.6 mi of:
- ASSI Portmuck
- ASSI The Gobbins
- SAC North Channel
1 protected feature
- Harbour porpoise Phocoena phocoena Favourable, 2019
- pSPA East Coast Marine proposed Special Protection Area, not yet classified
7 proposed features
- Great crested grebe
- Red throated diver
- Sandwich tern
- Common tern
- Arctic tern
- Manx shearwater
- Eider duck
Protected features and their latest condition assessment, from DAERA's 2023 marine protected area review. Only sites with a marine part are assessed there.
Alerts & advisories
Rip currents on surf beaches
The open Atlantic strands generate strong rip currents, particularly around low tide and after big swell. Swim between the red-and-yellow flags at lifeguarded beaches in season, never alone, and if caught in a rip do not swim against it: raise a hand, float, and let it carry you out until it releases.