At this time scuba diving is illegal from ay of the beaches in Chicago. It is legal from the chess pavillion at Oak Street. Check in with the guards trailer. This is not a complete listing nor is it an endorsement. It is your responsibility to verify credentials, air quality etc.
More info is available at underwater safaris.
Many of the numbers listed are dive shops or charter boats who have agreed to give information. Their names were eliminated due to lack of space. These numbers are correct as far as we know. Area codes change. This list is in the process of being updated for 2001.