That includes over 120 members of the Chicago Fire Department, including Commissioner Annette Nance Holt.
CFD isn't just jumping and will have dive teams in the water to make sure people are safe.
The Chicago Polar Plunge returns Sunday morning to North Avenue Beach.
The event, benefits Special Olympics Chicago and Special Children's Charities.
Commisioner Nance-Holt joined ABC7 to talk about this year's event.
Registration opens at 8 a.m., followed by an opening ceremony at 9:45 a.m. and then the plunge waves will take place from 10:30-11:15 a.m. For more information, visit sochicago.org.