Youngsters in Lichfield and Burntwood are being urged to sign up for the Ironkids challenge.
The junior event for three to 15-year-olds takes place at the Shugborough Estate on June 11 as part of the Ironman Staffordshire race weekend.
More than 300 children have already signed up to run between 500 metres and 2.5km.
Kevin Stewart, managing director of Ironman UK & Ireland, said: “The Ironkids events are always hugely popular and really do help ensure that Ironman is a family affair for all ages and abilities to enjoy.
“Entries are still open and this year there will also be reduced parking charges at the estate to make it more affordable for families to come along and cheer on the children taking part.”
For more details visit the Ironkids Staffordshire website.