Chicago Children's Museum (https://www.chicagochildrensmuseum.org/): Located on Navy Pier, this museum has interactive exhibits designed specifically for young children, including water play areas and creative play spaces.
Shedd Aquarium (https://www.sheddaquarium.org/): Kids often love the colorful and diverse marine life here. The interactive exhibits and touch tanks can be particularly engaging for little ones.
Lincoln Park Zoo (https://www.lpzoo.org/): This zoo is free and has a variety of animals that are sure to capture your toddler's interest. There are also playgrounds and a farm-in-the-zoo exhibit.
Millennium Park (https://www.chicago.gov/city/en/depts/dca/supp_info/millennium_park.html): The park has several features that are fun for toddlers, like the Crown Fountain and the spacious, open areas where they can run around. The park's playground is also a hit with young kids.
Boat Tours
The architecture boat tours are not very toddler-friendly, so here are some great alternatives: https://www.reddit.com/r/AskChicago/comments/1cxb7xm/is_the_architecture_boat_tour_the_best_boat_ride/?rdt=58317 The Chicago Fireboat sounds like where it’s at for kid-friendly: https://fireboattours.com/
Highly recommend sticking to public transit as much as possible when travelling with a toddler!
Chicago Transit Authority (https://www.transitchicago.com/)
Free Rides for Young Children: Children under 7 years old can ride free when accompanied by a fare-paying adult.
Source: https://www.transitchicago.com/for-parents-with-children/
Taxis are considered public transportation in Chicago so they don’t require car seats (note: ubers and other ride sharing services do require car seats):