Using an eSIM in Seoul

What Seoul is like on a phone

Seoul takes in shoppers, people following an artist's tour dates, people working with Korean companies, and weekenders who came because the flight is short. Dozens of subway lines run deep and far, and the network holds inside the tunnels between stations, not only on the platforms. The first surprise for a foreign visitor is usually not the signal at all — it is that international map services show incomplete walking directions here, so nearly everyone ends up downloading a domestic map app instead.

When you land

Most people come through Incheon (ICN), some through Gimpo (GMP), which sits closer in. Enable the eSIM on the aircraft so you have data for arrival paperwork and for finding the airport railway platform. The hour-long run into the city crosses reclaimed land and long water bridges with the line intact, though it wobbles in the tunnels near the end. Install a domestic map app and paste in your hotel address before you fly — Korean addresses follow a block system that is genuinely hard to read cold.

Where coverage changes

Almost everywhere in the city is strong, including inside moving subway trains — not only when they stop at a platform, which is not true of every metro. The underground shopping levels attached to stations behave normally. What changes is the hills: Seoul has real mountains inside the city, and the paths up to the old fortress wall or along the northern ridges soften in places, shadowed by rock faces and trees. The Han riverbanks are wide open and consistently good along their whole length.

What a day here costs in data

A sightseeing day sits around 1–2GB, between the domestic map app, sign and menu translation, and queue or booking apps for the restaurants people line up for. Anyone here for a concert or a fan event uses more, refreshing ticket pages and uploading long video afterwards. Shopping-led days tend to be lighter, because most stores have Wi-Fi. Downloading the Korean offline translation pack on day one removes a surprising amount of the background drain.

Districts travellers ask about

• Myeongdong — Cosmetics shops and food carts packed every evening; the line works but sags at peak, so open whatever payment or tax-refund screen you need before you join a queue.
• Hongdae — A university district of street music and late kitchens; the back lanes are tangled enough that the map sends you the long way round, so keep the venue name in Korean script to show someone if you get turned around.
• Gangnam — Offices and clinics over a long underground concourse beneath the main avenue, connected above and below; a straightforward place to arrange to meet, because the station exits are clearly numbered.
• Jongno and Insadong — Palace grounds and craft shops; the open courtyards are strong, while in the hanok alleys with high walls on both sides the map's idea of where you stand drifts a little.

Day trips out of the city

• The northern border area — Visits run through authorised tours, and photography is restricted at certain points. The road out is well served, but inside controlled areas follow the staff instructions exactly. Access conditions change with circumstances, so rely on the official notice rather than an older account.
• Suwon — Reachable on the same subway network; the old city wall makes a full circuit over low hills with a good line nearly all the way, dipping only for a moment inside the thick stone gatehouses.
• Nami Island — A train east, then a short ferry where the line dips briefly; on the island the tall avenues of trees create soft patches along the walking paths, so agree a meeting point before wandering off separately.