There are several stories of mermaids in Cornwall but the most well documented has to be the mermaid in Zennor.
For many years she used to attend church regularly, dressed in long skirts and never ageing, and no one knew who she was. A few of the local women would follow her when she left after the service but they always lost sight of her before she entered any house. She fell in love with a choir member, Matthew Trewhella, and slowly enticed him down to the sea-bed where they married. They had mer-children and lived happily. Matthew was never seen by human eyes again.
The mermaid however was seen again. Whilst out fishing a boat dropped anchor in Pendour (Mermaids) Cove and as the skipper was gazing over the side he was surprised to hear a voice coming from the sea. This was followed by a loud flapping sound. Looking down he saw a beautiful mermaid asking him to move the anchor because it was blocking the entrance to her underwater cave where her family lived. They were inside and she was trapped outside. It is said that on a still summers evening when the sea is smooth like glass, you can hear faintly drifting up from under the water, the two sweet voices of Matthew and his mermaid singing lullabies to their babies.
After Matthew disappeared his father, the local squire, commissioned a bench end be carved with a picture of the mermaid on, looking so radiant that maybe she would release Matthew from her spell and let him return to his family. This didn't happen and the bench end is still in Zennor church today. It has been dated as 500 to 600 years old.
Another mermaid lived at Lamorna and sat on Mermaid's Rock. Her singing would herald a shipwreck as she sat combing her hair. Her singing can still be heard today but don't be tempted to go to her, as you may never return.
Two separate harbours were blocked up with sand after curses by mermaids.
At Seaton Sands it was simply because some sailors insulted her but at Padstow it was more serious. Feeling lonely she lured a fisherman into her arms and as he made his escape he shot her. She lay dying and her final words were a curse on the harbour. Soon a storm blew up destroying several vessels and throwing up a huge bank of sand known now as The Doom Bar. This sandbank has caused hundreds of ships to flounder over the centuries.
At Cury, near the Lizard, an elderly man found a mermaid stranded on the shore with no means of returning to the sea. He helped her down to the water's edge where she rejoined her family. As she swam away she gave the man three powers. He would be immune to the spells of witchcraft, be able to gain knowledge from the spirits and his family would possess for all time good luck. The only drawback was that she would someday return for him and take him to her kingdom under the sea. Nine years later she returned and the bewitched man vanished with her under the waves.