Airport kt booths charge 40,000 won for 30-day unlimited that throttles after 1gb daily. Same exact service costs 15,000 won at any myeongdong gs25 or cu convenience store.

Walk out incheon arrivals, take arex to seoul station, grab prepaid sim at convenience store before heading to accommodation. Or order klook pocket wifi pickup at arrivals - 8,000 won daily vs airport vendor ripoff prices.

Kakao map and subway map work perfectly on free station wifi if you're staying central. But having backup data helps when navigating bukchon hanok village narrow alleys where wifi disappears.