Best friends Jessie and Bobby raised over £700 for the Cystic Fibrosis Trust by taking part in a scootathlon on Sunday.
Jessie Green and Bobby Webster, both four, took on the challenge at Dorney Lakes, Windsor, for their friend Finley Shoults, who has cystic fibrosis.
The pair completed 390m on a scooter, 390m on a bike and a 250m run, they raised £720.
Jessie’s mum, Kelly Green, of Lewsey Farm, said: “The children had a great time and really enjoyed it, they did really well.
“I was very proud and overwhelmed at their willingness to take part and raise funds for cystic fibrosis.”
The national charity funds research into the disease and provides information and support for patients and their families.