From the Klook website I booked Arex express train tickets from the airport to Seoul station and also from the station to the airport at a cost of €11.60 for two people each way. The journey takes about 50 minutes. Very efficient and convenient service to reach the station in an economical way. It is also possible to buy tickets at the machines on site. Seating is allocated and luggage can be stored in the designated compartments. Very easy and intuitive to take this train, based on the number of carriages and seats allocated.

Easy to get to in the airport. Buy tickets near the entrance. Comfortable ride to Seoul Station, with free WiFi. If you plan to use the subway on your trip, buy a T-Money card from the friendly conductor who walks through the train. Have your mobile phone and credit card handy; they will walk you through the online purchase then hand you a card with something like 4,000 Won credit; enough for 2.x subway trips. Caveat: though the Seoul subway system is very nice, it's a bit of work to navigate with heavy luggage so I wouldn't recommend it on arrival or departure. There's often a long walk between connections, multiple escalators (may or may not have an elevator); and sometimes only stairs to be found.

This is an efficient, stress free and decent value way from Incheon Airport to Seoul train station. The carriage is clean and comfortable. There are baggage storage areas on the train, but not kits so it o pop it’s to Baird as early as possible.