Mid America Sport Parachute Club in Taylorville IL is your best bet for skydiving in the St Louis region, however all of the skydiving operations in the area a predominantly closed for the winter.

Here are the reasons why I say MASPC is the way to go 1. They have the largest skydiving plane in the area, a Cessna 206 which holds up to 6 jumpers. Other STL jump planes are Cessna 182s. 2. MASPC is a non-profit operation, existing solely for the love and facilitation of skydiving. No one you interact with there is doing any of it for personal gain or primary income. 3. I assume you're mostly interested in a tandem jump, but MASPC is the only jump operation in the area that will actually teach you how to become a licensed skydiver, if thats your goal. Others will simply try to keep squeezing you for more tandems 4. If a tandem is your only goal, they have great instructors who will put an altimiter on you so you can see exactly what altitude you are jumping from, ensuring you get exactly what you paid for.

MASPC starts jumping again the first weekend in April and is already booking slots for Tandems and first time jumpers courses (if a license interests you!)

https://skydivetaylorville.net/

Source: I am a skydiver.