Two fire engines and 10 firefighters and officers were called to a fire at a park in Freemasons Road, Canning Town.
A climbing wall was destroyed by fire. An outbuilding was also damaged in the blaze.
The Brigade was called 2207 and the fire was under control at 2329. Fire crews from East Ham and Plaistow fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and Metropolitan Police Service.