A 13-year-old boy received extensive facial injuries after being assaulted at the Mandurah Skate Park overnight.
Police allege the teenager was struck in the face with a rubber hammer while at the skate park around 8pm on Sunday night.
It's believed the teen suffered multiple fractures to his eye socket and a broken nose.
He was taken to receive medical attention to treat the injuries.
A 15-year-old boy has been charged with assault occasioning bodily harm in relation to the incident and is due to appear in Perth Children's Court today.