It started as the sport of Hawaiian kings, on the clement shores of the paradise islands. But now claims are emerging that the origins of modern surfing can be traced to far-from-sunkissed Ireland.

Surfers all over the world, from the Californian coast to the swells of Lahinch owe their thanks to George Freeth, the son of an Irish immigrant from Ulster to Hawaii at the turn of the century.

According to the film Waveriders, to be released next month, a young Freeth's uncle (Irish/Hawaiian) gave him a traditional board at the end of the 19th century – a massive, solid wood plank that was 20 feet tall and weighed 200 pounds.

In a stroke of inspiration, the young Irishman decided to make it smaller. He soon became well known in Hawaii as the eccentric, pale-skinned man in the water with the small board. He even taught novelist Jack London to surf in front of a hotel at Waikiki.

In 1907 the young Freeth was invited to California to demonstrate surfing: Posters were put up around the Los Angeles area advertising a man who could walk on water. It was the start of the American west coast's love affair with surfing.

George died at the age of only 35 in the global flu pandemic of 1919. But by then he had sown the seeds of a pastime that would span the globe from Bondi Beach to Sligo.

Joel Conroy, the film's director, said he was amazed when he first heard Freeth's story.

"Being Irish myself I was intrigued when I heard about this character. But when people heard about it they thought I was completely bonkers. They said: 'An Irish guy started the surf scene? You've got to be crazy!', but it's true."

The film, narrated by Irish actor Cillian Murphy, traces the history of surfing's connection with Ireland from George Freeth to the present day, where Irish surfers have pioneered big wave riding, using jet-skis to tow themselves into the waves which are at least 20 feet high.

"What's happening in Ireland now is what happened in the USA in the 1950s and '60s. There's this real surf sub-culture that's starting to boom," said Conroy.

Kelly Slater, record-breaking, nine-times world surfing champion, affectionately describes Ireland's shores as "a cold paradise".

Andrew Cotton, a British semi-professional surfer, said: "We get big waves in England, but there are bigger waves in Ireland. The surf scene is being catapulted into the mainstream media because they are hearing about size of the waves and people are travelling from all over the world to surf them. In October I showed around two American surfers who had come over especially as they had heard the surf was good."