The beach at Porthor is known as the Whistling Sands, which in many ways is an odd name because squeaking sands would be more appropriate. As you walk along the beach the sand squeaks underfoot. I experienced a similar phenomena on Whitehaven Beach, Whitsundays, Australia beach and it’s distinctly odd.
One suggestion is that the sound is caused by friction as the grains rub against each other, but this isn’t proven. What is known is that you need the right sort of sand grains: ones that are near spherical with no sharp edges. This is probably why the effect is only heard on some beaches. The squeaking is most audible when the sand has been recently washed, and so it’s rarely heard far from the shoreline. On the beech, the sand needs to be dry (although submerged sand can also sometimes squeak)  so check the weather before travelling!
Logistics and some suggested locations
Whistling Sands – Porth Oer, Wales
Owned by the National Trust
Whitehaven Beach, Whitsundays, Australia
Can be reached via ferries and other boats.
Other reported sites
- Pilots beach in Laurieton, NSW
- Thistle Cove, Cape Le Grand National Park
- Neck Beach, Bruny Island, Tasmania
- Moreton Island, Australia
- Surfer’s Paradise, Australia
- Bondi beach, Australia
- Squeaky Beach, 5607, Australia
- Wilson’s Prom., Victoria, Australia
- Cocoa beach, Florida
- Treasure island, Florida
- Henderson Beach Destin, Florida
- Tybee Island, GA, USA