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Toxic Algae Warnings Prompt Swim Bans at Northern Ireland Beaches
27 Sep, 2025
Summary
- Temporary bathing advisories issued for Portstewart Strand and Downhill
- Blue-green algae detected at "red-alert level" at Portstewart Strand
- Visitors urged to avoid contact with water and keep pets away from shoreline
As of September 27th, 2025, visitors to Northern Ireland's north coast are being advised to avoid swimming at Portstewart Strand and Downhill due to the presence of blue-green algae. The Department of Agriculture, Environment and Rural Affairs (DAERA) detected the algae at "red-alert level" at Portstewart Strand earlier this week.
While Portstewart Strand and Downhill remain open to the public, officials are urging caution and advising people to steer clear of the water. The National Trust, which manages Portstewart Strand, has warned visitors not to swim, fish, wade, or use watercraft in the affected areas. Families and pet owners, in particular, are being asked to keep children and animals away from the shoreline.
The algae bloom has also been detected at Castlerock Beach, but no bathing ban is currently in place there. DAERA has stated it will continue to monitor the water quality and provide an update next week. The recent weather conditions have led to portions of the algal mats traveling along the Lower Bann River to the north coast, contributing to the outbreak.
