Seoul, the bustling capital of South Korea, is a popular destination for tourism and business alike. Unfortunately, that same popularity often leads to a fair bit of queuing at its main gateway, Incheon International Airport (IATA code: ICN). Today, we’ll try to beat the queues by checking in for our flight before we even leave the city.

Welcome to the Seoul Station City Airport Terminal.

Note: The information set out here is based primarily on a 06 February 2019 visit to the Seoul Station City Airport Terminal. Facilities and procedures were essentially unchanged when I used the CAT again on 25 March 2019.

Operating hours, check-in deadlines, train fares, and other details may change anytime without prior notice. Please refer to official sources – such as the A’REX website, the Incheon Airport website, and your airline’s own homepage – for updates and further information.

Our starting point is Seoul Station, one of the Korean capital’s key transportation hubs and the eastern terminus of the Airport Railroad line.

Deep in the bowels of this enormous building is the City Airport Terminal (CAT): a special facility that offers check-in and immigration services for passengers travelling on several Korean airlines. As of this writing (last checked on 27 June 2019), the list of carriers accommodated at the Seoul Station CAT includes Korean Air, Asiana Airlines, Jeju Air, T’way Air, Eastar Jet, and Jin Air. Note that there may be restrictions on the availability of CAT services for certain flights/destinations even amongst these eligible airlines; refer to the relevant pages of the A’REX website for details.

CAT services are provided free of charge, but you’ll need to hold an A’REX Express Train ticket in order to use the facility (more on this later).

There are several ways of reaching the CAT depending on one’s entry point. If you’re standing in Seoul Station’s cavernous main hall, simply head to the far western side – all the way across the concourse from the eastern side which sits closest to the subway lines – and home in on this large sign.

Go down a series of escalators – or use the lift if you’ve got heavy luggage in tow – until you reach the basement level (B2) where the Airport Railroad Express (A’REX) ticketing area is located.

Now then, let’s take this step by step.

STEP 1: BUY A TICKET FOR THE A’REX EXPRESS TRAIN.

Two distinct services ply the A’REX line. The All-Stop Train pauses at a number of intermediate stations en route to ICN, taking approximately 59 minutes to reach Terminal 1 (T1) and 66 minutes for Terminal 2 (T2). The standard adult fare from Seoul Station on this service is KRW 4,150 for T1 and KRW 4,750 for T2.

The faster, non-stop Express Train completes the journey to T1 in about 43 minutes, with T2 taking an extra 8 minutes. KRW 9,000 is the flat adult fare for this service, whether one gets off at T1 or T2.

It’s worth bearing in mind that customers of certain airlines and shopping establishments qualify for discounted Express Train fares. I only had to pay KRW 7,500 for a reserved seat on the train (plus a refundable KRW 500 deposit for the touch card ticket), thanks to a coupon received from Lotte Mart.

Now for a very important caveat. In order to use the CAT facilities, you’ll need to show a paid ticket for the Express Train. A ticket for the cheaper All-Stop Train won’t qualify you for CAT services.

Express Train tickets can be purchased from vending machines (on the right side of the picture) or from a manned counter (on the left). Head for the manned counter if you’re planning to avail of an airline or retailer discount.

Be sure to check which ICN terminal serves your airline before booking a seat on the train. (Needless to say, terminal assignments may change anytime without prior notice.)

Here’s the posted timetable from Seoul Station to ICN as of 06 February 2019, the day on which I most recently used the CAT.

Note the sign on the counter: same-day tickets only. You can purchase a ticket well ahead of your preferred schedule – I did that myself, booking a late-afternoon train on the morning of my departure – but you can’t book a seat for a future date.

You’ll be issued two items that, together, comprise the A’REX boarding ticket. A printed slip of paper (left) contains details of your selected train schedule and car/seat assignment. A touch card (right) will open the automatic turnstiles that allow access to/from the train platforms.

A KRW 500 deposit for the touch card is added to every purchase. After exiting through the last set of turnstiles at the end of your journey, insert the card into a refund machine to reclaim this deposit.

STEP 2: CHECK IN FOR YOUR FLIGHT.

With an A’REX Express Train ticket in hand, you’re ready to check in. The Seoul Station CAT counters are towards the right (past the immigration branch office) if you’re facing the manned ticket booth.

Operating hours are from 0520 to 1900 daily. Note that check-in deadlines vary depending on the airline: 3 hours 20 minutes before departure for Korean Air, 3 hours for other carriers.

Check-in procedures and counter arrangements may differ depending on your airline. In the case of Korean Air, separate lanes are provided for priority passengers (including First/Prestige Class) and everyone else.

The CAT check-in process is no different from what you might experience at a typical airport, except that you must also present a paid A’REX Express Train ticket (as proof of eligibility for the service).

After your bags are tagged and sent on their way down the conveyor belt, you’ll need to linger for a few minutes (the counter agent will specify how long) whilst your check-in luggage is scanned and inspected. If your name isn’t called by the stated time – which means that the scanners haven’t detected anything suspicious in your bags – then you’re free to move on to Step 3.

STEP 3: IMMIGRATION.

Our next stop is the Seoul Station branch of the Incheon Airport Immigration Office. Don’t worry, it’s right between the A’REX ticket counter and the CAT check-in area so there’s no need to run around in search of the place.

Bear in mind that the immigration office keeps different hours (0700 to 1900) from the check-in counters.

During the inspection, an immigration officer will check your passport and stamp your boarding pass. If there are no complications, the whole affair should only take a few moments.

STEP 4: RELAX.

This step is optional, and must be skipped entirely if the train you’ve chosen is scheduled to depart shortly. On the other hand, if you’ve completed all CAT formalities well ahead of take-off time, you might even head back out into Seoul – freed from the burden of heavy luggage – for some last-minute sightseeing.

Now if you’ve got some time to spare, but not enough to wander far, A’REX have set up a small waiting lounge for Express Train passengers near the ticket booth.

Don’t expect much – just chairs and tables, and a (surprisingly small) number of power points.

The posted operating hours of the lounge are 0530 to 2200.

STEP 5: BOARD THE EXPRESS TRAIN AND TRAVEL TO ICN.

Tap your way through the orange turnstiles using the touch card issued earlier…

…and take the lift down to the boarding platforms on level B7. Look for the door marked with the car number on your paper ticket and walk on board. (Just make sure that you’re getting on the correct service, not one that’s slated to depart before or after!)

Unlike the A’REX 2000 Series EMU rolling stock used on the All-Stop service – which were designed as normal commuter trains with bench-style seats and limited luggage space – the A’REX 1000 Series EMU employed for the Express has all the equipment one would expect to see on an airport train. There are dedicated luggage racks near the doors…

…and proper transverse seats with ample legroom. Bear in mind that about half of the seats in each car face away from the direction of travel – a quirk shared with first-generation KTX high-speed rolling stock – and none can be swivelled around. If this is likely to cause any motion discomfort, it’s probably best to specifically request a correctly orientated seat upon booking.

Note that these seats aren’t equipped with tray tables.

Right, away we go!

STEP 6: DISEMBARK AT ICN.

For journeys originating from Seoul Station, the Express Train will stop first at T1 before proceeding to the final station at T2. Make sure to get off at the correct terminal for your flight!

And one other thing: don’t forget to reclaim your KRW 500 deposit for the A’REX touch card by returning it at a ticket refund machine. There will be at least one standing close to the turnstiles after you exit.

Now then, whichever terminal you use, there will be a long but sheltered trek up escalators and through walkways towards the departures hall.

STEP 7: SKIP THE CHECK-IN AND DEPARTURE QUEUES BY USING THE DESIGNATED ENTRANCES.

Since you’ve already completed check-in formalities at the Seoul Station CAT, there’s no need to queue up at the ICN counters. Just head on over to the security/immigration zone leading to your terminal’s airside facilities.

Depending on the season and time of day, there may be long queues for getting to the security checkpoint – though things were fairly light on my 06 February 2019 departure from T2.

Now here’s the fun part: your CAT-stamped boarding pass entitles you to use the so-called “designated entrances”, normally reserved for special users such as flight crews and diplomats. Here’s one of the designated entrances at T1 (taken before a flight I boarded there last year), located along the shorter side of the frosted glass barrier that separates the security zone from the main check-in hall.

The ones at T2 are completely separate from the main entrances. Look for this sign and walk on through.

And that’s it. After the usual security check and immigration process (just a quick formality since you’ve already been to the immigration desk at the CAT), you’re free to enjoy the shopping and dining options available at ICN before the time comes to board your flight.

Cheerio.