1. Airport Limousine Bus to Downtown Seoul: US$ 10 One-Way
Between Incheon International Airport and downtown Seoul, a distance of 52km, diverse-transportation services are available. The Airport KAL Limousine Bus Line consists of 20 routes, connecting directly to most of the major hotels in Seoul as well as to key metro stations. It is popular for its low cost, US$10, and quality service. The spacious 25-seat luxury buses run every 10 to 30 minutes from 05:00 to 22:00.
2. Extensive Subway System in Seoul: Less than US$1 One-Way

The excellent subway systems in Seoul connect to almost every area of Seoul. It is a very convenient way to reach the hotels or filely anywhere in the city.
The Incheon International Airport, Gimpo Airport and Seoul Station will be connected with high-speed railroad by 2010. Using the Seoul's eight metro subway lines, one can go anywhere in the city within an hour.

The subway is efficient and convenient; an excellent way for foreign travelers to get around Seoul because station names, ticket counters, and transfer signs are all clearly marked in English.
Station arrival and transfer announcements are also in English and the lines are color-coded.
The trains are clean, safe, frequent and air-conditioned, and fares are extremely inexpensive: a one way trip usually cost about US$ 1.

3. Taxis: Around US$40 from Airport to Downtown Seoul
Taxis are a popular form of public transportation in Korea. There are basically two types: regular taxis and deluxe. Fares are metered. Regular taxis are about US$1.5 dollar for the first 2km and 10 cents for each additional 250-meters; depending on traffic, the fare from Incheon International Airport and downtown Seoul is usually around US$40(except tollgate fee). Deluxe taxis are about US$2.5 for the first 3km and 20 cents for each additional 250 meters.