Most states have a free day here and there. Missouri has whole free cities. St. Louis funds a regional Zoo-Museum District tax that keeps the Saint Louis Art Museum, the Saint Louis Science Center, and the Missouri History Museum free for everyone, every day — no resident requirement, no special date. Kansas City answers with the Nelson-Atkins Museum of Art, free to all by its founders' bequest, and the contemporary Kemper, also free. So in Missouri the question isn't usually 'when is it free?' — it's already free. The recurring deals below are the bonus: the Magic House children's museum opens free one Friday a month, and the Missouri Botanical Garden waives admission for area residents on weekend and midweek mornings. Every entry was checked against the museum's own admission page.
A few notes for planning: the always-free museums often charge separately for blockbuster special exhibitions and for add-ons like the Science Center's OMNIMAX, so the free part is general admission to the permanent collections — which is the bulk of what there is to see. In Kansas City, the paid history museums cluster cheaply: the Negro Leagues Baseball Museum and the American Jazz Museum share a $10 combo ticket in the historic 18th & Vine district, and the National WWI Museum and Memorial offers free admission on a handful of patriotic holidays each year. St. Louis EBT cardholders also qualify for reduced admission at the Botanical Garden and other ticketed attractions through Museums for All.
St. Louis
The Magic House, St. Louis Children's Museum
Regularly $15St. Louis's beloved hands-on children's museum in Kirkwood opens free every third Friday of the month from 5 to 8 p.m. through Free Family Nights, sponsored by Emerson. A single family — up to two adults and four children — gets in at no cost. It's first come, first served with no reservations, and capacity is limited, so arrive early. The 2026 dates are posted on the museum's site (June 19, July 17, August 21, and on through December).
🌐 Check current dates →Missouri Botanical Garden
Regularly $16 adultsOne of the oldest and grandest botanical gardens in the country — home of the geodesic Climatron and a serene 14-acre Japanese garden. St. Louis City and County residents get in free on Wednesday and Saturday mornings until noon with proof of residency. Everyone else pays $16 (kids 12 and under are always free). Aim for a weekend-morning visit if you live in the area, and budget extra time for the children's garden in season.
🌐 Check current dates →Always Free in Missouri
No free day needed — these flagship museums never charge general admission.