The boy, who has not been named yet, was last seen leaving Newquay's sports centre on his own at around 3pm. He was wearing a red Manchester United tracksuit top, football socks and white football boots.
Police have declared the incident high risk due to the boy's age and are appealing for information.
Anyone with information is asked to call 999 and to quote crime reference 04/16/03.
More top news
Davis wants the UK wants to maintain "close, even-handed co-operation" with EU regulatory authorities after it leaves the bloc.
The devices cause dogs to yelp, squeal, crouch and exhibit physiological signs of distress.
A frost-free night for most but chillier than previous nights.