The food chain says it hopes to get families excited about London 2012 and encourage kids to take part in sports.
The ‘Mascotathon’ promotion, which launches Wednesday (18 April), will run until the Games.
McDonald’s says it will give away 9 million activity toys that include counters so that children can keep track of the activity they do.
The activity they clock up on the toys can then be uploaded onto an online registration which enters participants into a draw to win tickets for the Games, an opportunity to meet Olympians and behind the scenes access.
Macey, Wenlock and Mandeville appear at McDonald’s restaurants around the UK during the summer as part of the campaign.
A second phase of activity will kick off in July giving away vouchers for free local sports sessions around the UK.