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Swim NI

Navigating the bathing season

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Swim NI is your number-one safety guide to a successful day at the beach, offering exclusive updates on existing water conditions at some of Northern Ireland’s best coastal spots during the bathing season. 

Powered by computer modelling technology, it predicts the state of our seas so that bathing is as clean and easy as it should be.

You can also follow Swim NI on Facebook and Twitter.

Predicted conditions

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Safeguarding your swim – why it’s important

Clean waters are central to our physical and mental wellbeing, giving us an important food source and vast open spaces for recreational activities. However, when levels of water pollution increase due to events such as flooding, animal fouling or low annual sunlight, it poses potential risks to our health.

Swim NI is an early warning system that protects bathers against exposure to two types of bacteria – intestinal enterococci and escherichia coli (E. coli) – that may lead to unpleasant illnesses like gastroenteritis and ear infection.

The service operates from 01 June to 15 September (the bathing season) and covers six beaches throughout Northern Ireland: Ballyholme, Ballywalter, Castlerock, Newcastle, Portrush (Curran) and Waterfoot.

How it works

Water samples are collected from the six bathing sites on a weekly basis, tested in a laboratory for bacterial levels and the results are determined. However, rather than relying solely on this approach, which can take up to 48 hours to complete and lag behind real-time conditions, a predictive computer model is also used in conjunction with this data to generate more accurate daily bathing quality updates.

The prediction model analyses up-to-date rainfall levels and historical site samples to classify water levels as either excellent or poor. These predictions are then communicated each day during the bathing season through the Keep Northern Ireland Beautiful website and onsite electronic beach signs.


From 2014-2020, Swim NI was formerly known as EU Swim – a cross-border research programme aimed at developing a live bathing water quality prediction system for six beaches in Northern Ireland and three in the Republic of Ireland (Enniscrone, Lady’s Bay, and Clogherhead).

The project was funded by the EU’s INTERREG VA programme, managed by the Special EU Programmes Body (SEUPB), and match-funded by the Department of Agriculture, Environment and Rural Affairs in Northern Ireland (DAERA), and the Department of Housing, Planning and Local Government in Ireland. Total investment amounted to €1,048,966.90.

EU Swim Project History

The previous lead partner in the project was University College Dublin (UCD), supported by Agri-Food and Biosciences Institute (AFBI) and Keep Northern Ireland Beautiful. Upon its completion in December 2020, UCD transferred all six NI-based bathing water quality prediction models to AFBI, who continued to refine the models by gathering environmental water samples over the 2021 bathing season. Since September 2019, DAERA has approved funding for a new EU Swim legacy project, Water Quality Prediction Models Impact DAERA Schemes (WQPMIDS), that would retain AFBI as research partner and Keep Northern Ireland Beautiful as communications partner. 

On 01 June 2022, Swim NI launched to coincide with the beginning of the bathing season. The original predictive aim of the project remains intact and all Northern Ireland beach locations are unchanged.


For any enquiries, please get in touch: enquiries@keepnorthernirelandbeautiful.org.

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