Check the transportation
If there is no one to ask about how to get to your hotel, you will have to make decision which transportation you will take. Seoul has many transportation systems to take you to your hotel; subway (aka AREX), airport limousine, or taxi. Among those, we recommend you to take AREX, especially, if you are staying at one of guesthouse at Hongdae area. It takes only 40~50 minutes to get in the center of Seoul and cheaper than take airport limousine or taxi. bAREX English website (SOURCE: https://english.arex.or.kr/jsp/eng/main.jsp)
If you are staying at one of major hotels, there will be airport limousine bus to take you right in front of the door (Click here for more detail). It usually takes about 1.5 hours, but remember! Korea is one of worst traffic jam countries. There is no traffic jam on AREX So, decision is up to you
AREX Station is on the B1 floor in the Transportation Center at Incheon airport. To see the direction to station, see station information page on the AREX website. (Click here for more detail). Still confusing? Then, ask information desk. They will be more than happy to let you know how to get there.