Enniscrone Pier has been issued with a Do Not Swim warning due to the risk of deterioration in water quality.
Sligo County Council have said that bathing could cause illness and that the likely cause is high levels of rainfall resulting in increased levels of bacteria in the water.
However, it is expected that this will be a short-term issue.
Beach users have been told they should wash hands before handling food, avoid swimming with an open cut or wound if you are pregnant or have a weakened immune system and avoid swallowing or splashing water.
The HSE have been advised and follow up monitoring has been arranged while the notice will remain in place until water quality returns to an acceptable standard.
