Telecom

A Korean mobile number in your own name is not a convenience here, it is infrastructure. Identity verification on Korean websites keys off a number registered to you, so without one you cannot use banking apps, book a hospital appointment, buy concert tickets or order a delivery.

Which makes this the second thing to arrange after your residence card, and worth getting right.

What the number actually unlocks

It is worth seeing the list, because it explains why this ranks above almost everything else in your first month:

• Banking apps and online transfers, which verify you by phone before letting you move money. Banking covers the rest.
• Hospital and clinic booking, and the patient portals that hold your results. Medical and health covers finding care.
• Government and immigration portals, including appointment booking. Legal and administrative covers what you will be filing.
• Delivery, transport and ticketing apps, which is most of daily convenience here.
• Second-hand marketplaces, where departing residents sell entire flats of furniture.

Almost none of this works on a number registered to somebody else, which is the practical reason not to borrow one.

Prepaid first, contract after

On arrival you need to be reachable before you have a residence card. A prepaid SIM works on your passport and is sold at airport counters and convenience stores. Take one, accept that it is poor value, and treat it as a bridge.

Once the residence card arrives, move to a postpaid plan in your own name. That is the one that unlocks identity verification. Some operators also want a minimum period remaining on your visa, so carry your card and your passport.

Carriers and the cheaper option most people miss

Three operators own the networks. Alongside them a large number of budget operators resell the same networks at substantially lower prices - identical coverage, identical speed, a fraction of the monthly cost. They advertise less, sell more online than in shops, and are the best value in the country.

	Suits
Major carrier, contract with handset	You want a new phone financed over the term
Major carrier, SIM only	You want flagship customer service and in-person branches
Budget operator, SIM only	You brought your own phone and want the lowest bill
Prepaid	Your first weeks, or a very short stay

The discount nobody tells you about

If you bring your own unlocked phone rather than taking a subsidised handset, you can claim a substantial ongoing discount on the monthly plan instead of the handset subsidy. It is a choice between the two, not both, and the monthly discount is frequently the better deal over a two-year horizon.

Shop staff earn on handset sales and will not always lead with this. Ask for it explicitly, by name, and do the arithmetic across the whole term.

Check your phone is unlocked and supports the Korean bands before you rely on it. Most recent international models do.

eSIM

Supported by the carriers and by a growing number of budget operators, which is useful for keeping your home number active alongside a Korean one on the same handset. It also removes the trip to a shop. Confirm the operator supports eSIM for foreign residents specifically, because the activation flow sometimes assumes a Korean ID.

Coverage

Among the best in the world, and worth stating because it changes assumptions people arrive with. Signal holds in subway tunnels, in lifts, in basements and on mountain trails, and public wifi is widespread in stations, buses, cafes and government buildings.

The practical consequence is that you can pick a cheaper plan with less data than you would at home and rely on wifi more than you expect. Rural and island coverage is good, though a remote valley will still drop you.

Home internet

Fast, cheap and installed quickly, with gigabit widely available and a technician usually within days. Contracts typically run two or three years with meaningful cash incentives for signing, often bundled with television.

Two things to know. The incentive is negotiable and varies by reseller, so it is worth comparing more than the headline monthly price. And if you live in a building with an existing arrangement, your choice may be limited to one provider, so ask the landlord or management office before you sign anything.

For a short stay, a pocket router or simply a generous mobile data allowance is usually the better answer than a three-year contract.

Keeping your number, and leaving

Number portability works between operators and takes minutes, so switching to a cheaper plan does not cost you your number. That matters, because your number is attached to your identity verification across every service you have registered.

Cancel properly before you leave Korea. A contract left running keeps billing, and an unpaid telecom debt is the kind of thing that surfaces awkwardly if you later return. Early termination inside the committed term carries a fee, and if you took a subsidised handset the remaining instalments become due. Visit a branch with your residence card, settle the account and get written confirmation.

Where this goes wrong

• Staying on prepaid. It does not give you reliable identity verification.
• A contract in somebody else's name. It breaks verification for everything, and it is a bad idea for other reasons.
• Not asking for the bring-your-own-phone discount. It is the saving most foreigners miss.
• Paying full carrier prices when a reseller uses the same towers.
• Signing a three-year internet contract for a one-year posting.
• Leaving the country without cancelling. The billing does not stop.

Where to go next

Account opening is the next step, since most banks want a Korean number. Essential living covers the order the whole setup runs in.