Lisfannon is classified as achieving Good Water Quality in 2025 based on the assessment of bacteriological results for the period 2022 to 2025. Lisfannon has achieved a Good Water Quality rating for the four consecutive years 2022 to 2025. 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.

Lisfannon beach consists of a sandy beach along the Swilly Estuary. Lisfannon is estuarine in character, with shallow water and intertidal sand and mud flats being the dominant habitats. These are exposed at times during the tidal phase during the day. These habitats support a wide variety of plant species and wildlife, including otters. This site is of high conservation value because of the extensive area of relatively unspoilt coastal habitats and the range of plant and animal species that these habitats support. Activities at Lisfannon Beach include swimming, surfing and other land-based activities such as football, kite flying, etc. The bathing area is designated and is approx. 0.6217 km2 and the extent along the water is approximately is 2020 m. The depth of the water on the shoreline increases within 2 meters off the shore to a depth of 0.5 meters and gradually increasing.