Surfers Against Sewage will host a festive-themed cold water swim this Christmas.
The charity, along with Plastic Free Falmouth, is inviting people to join in the second "Santas Against Sewage" cold water swim on December 14.
It will take place at Gyllyngvase Beach from 12pm to 1pm.
Last year, many groups came together for a swim to raise awareness of sewage pollution in Cornwall.
The swim turned into a protest after a sewage discharge.
The charity says that since last year, the pollution problem has only worsened.
The industry regulator Ofwat’s annual report found there has been an 80 per cent year-on-year increase in serious pollution incidents from South West Water.
Jess Morris, an SAS local rep for Cornwall, said: "This year, we are attempting to dip again to show South West Water – Cut the Crap and stop the polluting of our waters.
"We are proving that using the water is important for us all year round, for our health and mental wellbeing.
"Pollution is stopping that and preventing us from doing what we love.
"Not to the mention the impact on our amazing local ecosystems and seagrass beds."
The charity is encouraging people to wear their best festive attire and brave the cold water to show their commitment to safeguarding the oceans.
They say it is a "festive and impactful way to make a difference while having fun."
Surfers Against Sewage describe themselves as a "campaigning charity made up of water lovers, who protect the ocean and all it makes possible."
They say: "We fight against the polluters and campaign for a thriving ocean, thriving people.
"We take action on the ground that triggers change at the top.
"Action from the beachfront, to the front-bench."
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