Most advice about navigating Korea offline skips the useful part, which is that Seoul spent a great deal of money making sure you are not offline.
The city runs a free public Wi-Fi network called 까치온 (Kkachi-on) from about 24,060 access points, carrying more than 1.28 million users a day. No sign-up, no identity check, no fee. A visitor who landed an hour ago uses it on exactly the same terms as somebody who has lived here for thirty years.
Connecting takes one word
Choose the network called SEOUL_Secure. Enter Seoul as the username and Seoul as the password.
That is the whole procedure, and you only do it once. After the first connection your phone joins by itself anywhere the network reaches.
On the bus, which nobody tries
The coverage list runs through the places you would guess: main roads, parks and walking paths, bus stops, traditional markets, tourist sites, public buildings.
Then it includes the buses themselves, both the city routes and the smaller neighbourhood ones. A Seoul bus is a moving hotspot, which turns the least predictable part of a journey into the part where you can actually look things up. If your phone has been sulking all afternoon, the bus is where it recovers.
Seoul publishes every access point on its Smart Seoul Map, under the city-life layer, if you want to see the shape of the thing rather than trust it.
Where it stops
This is a city network. It belongs to Seoul and it ends where Seoul does.
Other cities run their own schemes on their own budgets and their own standards, so do not carry an assumption over the boundary with you. And out on a ridge above a valley, or on an island with one ferry a day, the question is not which network to join. There isn’t one.
That is the case for a data plan rather than a Wi-Fi habit. A data-only eSIM costs very little for a week, and the connectivity comparison covers what each option does and does not unlock.
What I will not tell you to rely on
You will find confident instructions for downloading offline maps inside the Korean map apps.
I could not verify them. Naver and Kakao do not document the behaviour clearly, the accounts contradict each other, and the parts you would most want when lost still need a signal no matter what is cached: live bus arrivals, and a route that recalculates when you walk the wrong way. Treating an undocumented feature as a safety net is how people end up standing still.
So prepare the way you would for a place with no coverage at all, and enjoy the Wi-Fi as a bonus when it appears.
The offline kit, which is mostly screenshots
Before you leave the hotel, capture the route as an image rather than a plan that needs fetching. A screenshot survives a dead signal, a dead app and a foreign SIM.
Save the destination in Hangul, not romanised. If you have to show a stranger or a driver where you are going, Korean text works and a Latin transliteration makes them do the conversion in their head. The address guide explains why, and how to read what you are looking at.
Write down the exit number. It is the most compressed piece of navigation in this country: one number that puts you on the right corner of the right junction, and it costs nothing to note before you lose signal. The exits guide covers how they are arranged.
And know the last train. Running out of battery at midnight is an inconvenience; running out of trains at midnight is a taxi fare across the city.
The Kkachi-on figures come Seoul Metropolitan Government’s own published description of the service, read on 14 September 2026: roughly 24,060 access points, more than 1.28 million daily users, the SEOUL_Secure network name, the username and password both being Seoul, the one-time connection, and the list of covered locations including city and neighbourhood buses. The same page points to the Smart Seoul Map for access point locations. Offline map support in the Korean map apps is deliberately not stated here: the claims circulating are not backed by documentation from either company, and I would rather leave a gap than fill it with something I could not check.
