The Haslingden High School Year 8 student competed in the North West Open Water Swimming Championships at Salford Quays.
The 13-year-old from Norden said: “I swam in a wetsuit because it was colder out of the water than it was in it, but although it gives you more buoyancy it restricts your reach so I could not swim as fast.
“It was a cold day and quite windy and at first, when I got in the water, there were so many people swimming I got a bit knocked about so I decided to hold back.
“Six of the swimmers got out early because of the cold conditions and as a result of suffering from cramp.
“I finished third in the North West region and second in Lancashire and earned a place in the national final at Rother Valley in Sheffield on July 24.”
Beth swims with Pioneer 79 in Accrington every week after school from Monday to Thursday and again on a Saturday.
She only got the chance to do a couple of open water swims in Elton Reservoir ahead of the competition.