The event, which runs until September 5, 2025, has been launched at the three Bexley Leisure Centres and offers children the chance to complete activities and sports to finish the challenge.
Participants can then get a free session after completing 10 activities.
To combine fitness and fun, the centres are allowing children to collect stickers after each visit.
Upon completing all 10 activities, participants can hand in their card and get their next session for free.
The activities on offer include swimming, soft play, and group exercise classes for those aged 16 and older.
The scheme is designed to encourage families to get outside and exercise during the holidays.
The leisure centre expects individuals will be able to keep on track with their own fitness goals during this time.
For more information, people can visit the website (leisurecentre.com/summer-of-fun) or contact Crook Log Leisure Centre on 020 8304 9090, Erith Leisure Centre on 01322 350271, and Sidcup Leisure Centre on 020 8302 0556.
All information can also be found on its website.