Hong Kong's Ryan Leung is the first person from the SAR to successfully swim across the North Channel, between Ireland and Scotland, one of the marathon swimming challenges of the Oceans Seven.

The 35-year-old swam 40 kilometres in 14 hours and 5 minutes with the swim ratified by the Irish Long Distance Swimming Association.

In an Instagram post, the swimmer said he spent more than three hours on the last seven kilometres due to the current.

He also wrote: "not fast but once again my fat is proven life-saving – average water temperature is 12.7 degrees Celsius, but I am sure most of it was 11 degrees."

Leung, who used the challenge to raise funds for charities supporting grassroots youth development, thanked his fans for all their support.