Is AREX enough on show day?

Often yes to Seoul Station, then subway. Build 90+ minutes from ICN immigration to gate for evening shows.

Can I leave luggage at the venue?

Usually no. Use airport/station lockers or a luggage service named in the notice.

Venues · 인천·김포 공항에서 서울 K-pop 공연장까지

ICN / GMP airport to Seoul K-pop concert venues

ICN → Seoul Station / Hongdae — AREX express or all-stop; then Line transfers toward Jamsil, Olympic Park (KSPO) or Dongdaemun areas.
Gocheok Sky Dome — often Line 1 / Gyeongui–Jungang toward Gocheok; leave buffer for bag check.
KINTEX (Ilsan) — longer ride; check event shuttles on the promoter notice.