Here are the locations for tax refunds at Incheon International Airport:
 

Terminal 1 (3rd Floor - Departures)

- General Area (Before Security): Tax refund kiosks are located near Check-in Counters B, E, J, and L. If your refund requires customs verification (typically for refund amounts over 75,000 KRW or random selection), the customs declaration desks are located right near these areas. You can also drop off your checked baggage there after verification.

- Duty-Free Area (After Security): Kiosks and refund counters to collect your cash are located near Gate 28.

- Concourse: There are also facilities in the center of the 3rd floor of the boarding concourse.
 

Terminal 2 (3rd Floor - Departures)

- General Area (Before Security): Tax refund kiosks and customs declaration areas are located near Check-in Counters D and E.

- Duty-Free Area (After Security): Refund locations are available near Gates 249, 250, and 253. You can collect your cash refund in the lounge opposite Gate 249.

Here is the link of Incheon Map 
https://www.airport.kr/geomap/ap_en/view.do?type=2&alertType=0&tmnlId=P01#/search/item/61022 

Look for this icon on the map

(Icon graphic courtesy of Incheon International Airport Corporation.)

You may change Terminal and floor view in the top left corner!

For an example video check out our instagram: https://www.instagram.com/chingu_mobile/