Half Moon
Co. Dublin, Dublin City Council. Sea bathing water.
Icy.ie is a data aggregator, not a safety assessment.
Swim status: CAUTION
- No temperature sensor within 25 km, so the water temperature here is unknown.
- It is dark or close to dark here (sunset 18:24, first light 07:22).
- No lifeguard is listed for this beach.
Conditions can change. Check flags and signs, never swim alone, know how to Float to Live. Float to Live | Cold water checklist
EPA alert details
Short-term pollution risk. The EPA lists this water as prone to short-term pollution, for example after heavy rain. Wait at least 48 hours after heavy rain. Icy.ie does not check rainfall.
Before you go in
- Water qualityLast sample 9 September 2026, rated Good.
- Water temperatureNo nearby sensor within 25 km. Assume it is cold: cold water shock can occur below 15°C.
- LifeguardsNo lifeguard is listed for this beach.
- DaylightSunrise 07:57, sunset 18:24 today. It is dark or close to dark now.
- TideModelled as falling, low water about 23:30. Confirm with local tide tables.
- Waves and wind0.4 m waves (offshore buoy, 51 km away); 9 knot wind from NE (38°) (offshore buoy, 51 km away). Conditions at the beach can be very different.
Read before you swim: cold water safety checklist, cold water shock and Float to Live, bathing water quality, tides and currents, jellyfish and stings.
Latest water quality sample
Good
Sampled 9 September 2026 (39 days ago)
- E. coli
- 279 per 100 ml
- Intestinal enterococci
- 23 per 100 ml
Routine monitoring runs from 22 May to 15 September. There is no routine testing in winter, so a sample can be months old. A sample shows one moment, and conditions can change quickly after rain.
Icy.ie checked 18 Oct, 21:49. Sample date 9 September 2026. Source: EPA.
Tide at the beach
Falling
Modelled height now -0.4 m at 21:50
- Next high water
- 06:20 tomorrow, 0.5 m
- Next low water
- 23:30, -0.6 m
Next 24 hours
- Low23:30-0.6 m
- High06:200.5 m, tomorrow
- Low11:50-0.5 m, tomorrow
- High18:400.8 m, tomorrow
Times are Irish local time. These are modelled predictions at the nearest model point, 0.2 km from the beach. They are not a substitute for local tide tables, and do not include weather effects such as surge and wind. Heights are relative to the model's mean level, not chart datum. See tides and currents.
Icy.ie checked 18 Oct, 21:49. Source: Marine Institute model.
Sea temperature
No nearby sensor
No Marine Institute sensor is within 25 km, so we do not give a headline figure that would not describe this beach.
Offshore buoy, 51 km away, can be several degrees different from the beach: 14.6°C, read 18 Oct, 21:00 (50 min ago) (M2 weather buoy, Irish Sea).
Water near the shore, in shallow bays and in estuaries can be several degrees colder or warmer than a sensor offshore. More at Irish sea temperature today.
Icy.ie checked 18 Oct, 21:49. Source: Marine Institute.
Waves and wind
- Wave height
- 0.4 m
- Wave source
- Offshore buoy, M2 weather buoy, Irish Sea, 51 km away, 18 Oct, 21:00 (50 min ago)
- Wind speed
- 9 knots
- Wind direction
- From NE (38°)
- Gusts
- 11 knots
- Air temperature
- 11.9°C
- Wind source
- Offshore buoy, M2 weather buoy, Irish Sea, 51 km away, 18 Oct, 21:00 (50 min ago)
Offshore sensors differ from your beach. Waves and wind at a buoy far out can be stronger or weaker than at the shore, and a beach sheltered from one direction may be exposed to another.
Icy.ie checked 18 Oct, 21:49. Wind reading 18 Oct, 21:00. Source: Marine Institute.
Daylight today
After sunset
- First light (civil twilight)
- 07:22
- Sunrise
- 07:57
- Sunset
- 18:24
- Last light (civil twilight)
- 18:59
Plan to be out of the water before sunset. Read dawn, dusk and night swimming safety.
Calculated by Icy.ie for this beach's position. Irish local time. No data feed is used.
Not checked by Icy.ie
These matter for your safety and are not in our data. Check them yourself before you go in.
- Beach flags. Obey lifeguard and red flags. Safety checklist
- Rip currents. Tides and currents
- Met Éireann warnings. Check current weather warnings and the marine forecast. Storms and swell
- Jellyfish and algal bloom. Marine hazards
- Storm overflow and sewage discharge. Bathing water quality
Facilities
- Blue Flag
- No
- Green Coast
- No
- Toilets
- No
- First aid
- YesYes
- Lifebuoy
- YesYes
- Lifeguard
- No
- Parking
- YesYes
- Dogs
- On a leadYes
- Accessible
- No
- Beach wheelchair
- No
Icy.ie checked 18 Oct, 21:49. EPA record last updated 31 March 2026.
Water quality class by year
| Year | Annual class |
|---|---|
| 2025 | Excellent |
| 2024 | Excellent |
Half Moon is classified as achieving Excellent Water Quality in 2025 based on the assessment of bacteriological results for the period 2025 and 2024. Half moon received an Excellent Water Quality result in 2024. Half moon was newly identified in 2024 as a beach for monitoring, management and assessment under the requirements of the 2008 Bathing Water Quality Regulations. Annual water quality ratings are generally calculated using monitoring results over a four-year period and are assessed against stringent bacterial limits to protect bather health.
An annual class summarises four years of testing. It does not describe the water today.
Icy.ie checked 18 Oct, 21:49. EPA record last updated 31 March 2026.
About this water
The Half Moon Bathing Water is located approximately half way along the Southside of Great South Wall. It is not a beach and access to the bathing water is via ladder or slipway from the Great South Wall. Access for pedestrians along the Great South Wall is permitted solely by foot or bicycle. Vehicle access (except for emergency vehicles) is limited at the beginning of the wall, where bicycle parking and car parking facilities are located. For additional parking, it is encouraged to use the nearby Shelley Banks car and bicycle parking facilities and refrain from parking along the roadway to prevent disturbance/damage to sand dunes. The bathing area is bounded by the Great South Wall to the North and the Irish Sea to the South thus flora and fauna have limited opportunity to grow. However, due to its position and coastal connection to Sean Moore Park and the Irishtown Nature Reserve, it is of international importance for migrating Light-bellied Brent Geese and of national importance for nine other waterfowl species. The Half Moon bathing location is located within the South Dublin Bay and River Tolka Estuary Special Protection Area (SPA), the South Dublin Bay Proposed Natural Heritage Areas and South Dublin Bay Special Area of Conservation (SAC). It is encouraged to check wind, weather and tidal forecasts before swimming. During times of adverse weather, Dublin Port Company ( https://www.dublinport.ie/public-notices/ ) and Dublin City Council will issue a public safety notice for the temporary closure of the Great South Wall.
Profile for Half Moon for 2025
Icy.ie checked 18 Oct, 21:49. EPA record last updated 31 March 2026.
Where the data comes from
Bathing water details, classifications, samples and alerts: Environmental Protection Agency (Ireland), published under the Creative Commons Attribution 4.0 licence (EPA bathing water API).
Modelled tide, inshore and offshore buoy readings: Marine Institute (Ireland), published under the Creative Commons Attribution 4.0 licence via ERDDAP. Readings are provisional and can be missing or delayed. Icy.ie refreshes this page about every 10 minutes.
Sunrise, sunset and twilight are calculated by Icy.ie from the beach position.