Massive sea foam engulfs Port Noarlunga beach and spills into Onkaparinga River

Port Noarlunga Beach has been engulfed by an enormous amount of sea foam, sparking concern among locals and health authorities.

The unusual phenomenon, which is no longer confined to the shoreline, has reportedly begun creeping into the Onkaparinga River, raising fresh concerns for the region’s waterways.

Health authorities are now advising people with asthma to carry their medication when visiting beaches while foam is present.

Social media has been flooded with photos and videos of the thick, shaving-cream-like foam washing ashore.

The phenomenon has baffled locals before. In late August, dense sea foam inundated Henley Beach in Adelaide’s west, prompting warnings from the South Australia’s Department of Environment and Water.

While the cause of the foam at Port Noarlunga has not yet been confirmed, scientists warn that large accumulations of foam can pose health risks under certain conditions.

“Most sea foam is not harmful to humans and is often an indication of a productive ocean ecosystem,” Ocean Watch Australia said.

“But when large harmful algal blooms decay near shore, there are potential for impacts to human health and the environment.

“During blooms, popping sea foam bubbles are one way that algal toxins become airborne. The resulting aerosol can irritate the eyes of beachgoers and poses a health risk for those with asthma or other respiratory conditions.”

The South Australian Research and Development Institute previously tested waters off Henley Beach after reports of foam as authorities continue to monitor the impact of algal blooms, which have devastated parts of the South Australian coast since September 2024, killing thousands of marine creatures.

Residents are being urged to avoid swimming or surfing in foamy or discoloured water while authorities assess the Port Noarlunga situation.