Concerns were raised a pollution incident had taken place
Steve Bagnall and Tom Burnett Content Editor
23:06, 26 May 2026Updated 07:40, 27 May 2026
The sea turned brown at Porthdinllaen beach(Image: James Tatham)
This is the moment the sea turned brown at a popular north Wales holiday beach loved by Mancunians over the Bank Holiday weekend.
The murky water at Porthdinllaen in Gwynedd sparked fears over the weekend that a sewage leak had taken place at the famous North Wales beach.
However Natural Resources Wales [NRW] has now confirmed this was not the case, and the discolouration was actually caused by algae, NorthWalesLive reports.
Arfon Hughes, environment team leader for NRW, said: “Our officers received reports of potential pollution at Porthdinllaen beach over the bank holiday weekend.
“Upon inspection, this was found to be a type of non-toxic algae called Phaeocystis – one of the most common bloom-forming algae in our coastal waters.
“The blooms can form a brown, frothy scum that is harmless and may be influenced by recent sunlight and warmer temperatures.
“Anyone with concerns about potential pollution can report them to us by calling our 24/7 incident communication line on 0300 065 3000 or by using our online incident form.”
Porthdinllaen has a sweeping sandy bay sheltered by the Carreg Ddu headland. It is famed for its beach pub, Ty Coch, which has been named among the best beach bars in the world.