Terminal 1 (Concourses A and C) and Terminal 2 (Concourse E) are physically separate buildings — there is no airside connection. If you need to switch terminals you'll re-clear security.
4 post-security indoor SARAs (Concourse A near A16, Concourse C near C24, Terminal 2 near E4, Terminal 2 near E40), plus 2 pre-security outdoor areas (T1 outside exit 6, T2 outside exit 15). Each indoor SARA is 100 sq ft, wheelchair accessible, with a low-profile artificial-turf tub, decorative fire hydrant, wall hose for cleanup, waste bag dispenser, and sink.
Indoor 100 sq ft enclosed room with low-profile turf tub, fire hydrant, sink, wall hose for cleanup. Terminal 1 — Southwest, American, others.
Indoor 100 sq ft enclosed room, same amenities as A. Terminal 1 — Southwest dominant carrier at STL.
Indoor 100 sq ft enclosed room. Terminal 2 serves Southwest, Delta, and others depending on schedule.
Indoor 100 sq ft enclosed room, at the far end of Concourse E.
Outdoor gated 400 sq ft area with park benches, trash cans, fire hydrant. Some artificial grass rather than natural lawn.
Outdoor gated 400 sq ft area with park benches, trash cans, fire hydrant. Grassy surround with dedicated dog area.
Concourse A, near gate A16 · Indoor 100 sq ft enclosed room with low-profile turf tub, fire hydrant, sink, wall hose for cleanup. Terminal 1 — Southwest, American, others.
Terminal 1 Outdoor · Terminal 2 Outdoor
Given this airport's policy, use the pre-security area or relieve at home/hotel before arrival.