Before you start

Residence card with the address printed on it
A Japanese bank account or credit card, for most postpaid plans
An unlocked or eSIM-capable handset supporting Japanese bands
A Sapporo address, for fibre

Step-by-step

1
Bridge the first fortnight with a travel eSIM
A data-only eSIM bought before you fly covers you until the residence card and bank account exist, which can take two weeks. It removes the pressure to sign something unsuitable in week one.
Mobile appWho: YouDay 1
2
Go straight to an MVNO or a carrier sub-brand
IIJmio, mineo and the carriers' own low-cost brands run on the majors' networks at a fraction of the price with no long commitment. The flagship carrier plans are only worth it for bundled services you specifically want.
OnlineWho: You
3
Expect a Japanese payment method to be mandatory
Most postpaid plans need a Japanese bank account for direct debit or a Japanese-issued credit card, and foreign cards are frequently rejected. This is the practical reason the bank account comes before the phone.
OnlineWho: You
4
Check rural coverage if you plan to leave the city
Coverage inside Sapporo is excellent on every network. Once you are on a Hokkaido road with eighty kilometres between towns, the differences between operators become real, and docomo's rural footprint is materially better than the others'. Choose on that basis if you will drive.
OnlineWho: You
5
Order fibre early and ask what actually reaches the flat
Japanese fibre is fast and inexpensive, but a building advertised as fibre-connected may run fibre to the basement and copper to your door. Ask specifically whether it is fibre to the room. In Sapporo, engineer visits also slip in deep winter — order weeks ahead if your work depends on the line.
OnlineWho: You
6
Check whether the flat is heated electrically before you sign
Hokkaido Electric Power's household tariffs are among the highest in Japan. An all-electric flat with panel heaters looks modern and costs a great deal to run through a Sapporo winter; kerosene central heating is usually cheaper per unit of warmth. This is a lease-signing question, not an afterthought.
In personWho: You

Documents you’ll need

Residence card with address
Japanese bank account or credit card
Passport, occasionally requested
Proof of address, for fibre installation

Things most newcomers don’t know

The bank account gates the phone, not the other way round.

Most Japanese postpaid plans require a Japanese bank account or a Japanese-issued credit card, and foreign cards are commonly refused outright. Because the bank account needs ward registration and ward registration needs an address, the whole chain runs address, then ward office, then bank, then phone. Attempting it in any other order is where most first-fortnight frustration in Japan comes from.

Source: community-reported

MVNOs run on the same towers for a fraction of the price.

Government pressure on the three major carriers produced both low-cost sub-brands and a healthy MVNO market, all riding the majors' own networks. Coverage and speed are essentially identical outside peak congestion. Anyone paying a flagship price without needing the bundled extras is spending several times more than necessary for the same service.

Source: Ministry of Internal Affairs and Communications

Hokkaido is on the 50 Hz grid and has the country's most expensive electricity.

Japan is split between a 50 Hz east — which includes Hokkaido, Tōhoku and Tokyo — and a 60 Hz west covering Nagoya, Osaka and Kobe. A second-hand appliance bought from someone moving up from Kansai may not behave, and mains is 100 V regardless, so European appliances need a transformer. On top of that Hokkaido Electric Power's tariffs are among the highest in Japan, which makes electric heating a genuine financial decision.

Source: community-reported

Coverage differences between operators only matter once you leave the Ishikari plain.

Inside Sapporo every network works. Hokkaido is the size of Austria with a fraction of the population, and on the roads towards Furano, the Shiretoko peninsula or the far north the gaps between operators become visible and occasionally consequential — a breakdown in a February whiteout is not the moment to discover your MVNO's parent network is the thin one there.

Source: community-reported

Common mistakes to avoid

Trying to get a phone contract before ward registration and a bank account exist.
Paying a flagship carrier price when an MVNO on the same network costs a fraction.
Assuming a building's advertised fibre reaches your actual flat rather than its basement.
Signing for an all-electric flat without pricing a Sapporo winter on Hokkaido Electric Power's tariffs.
Buying a 60 Hz appliance from someone moving up from Kansai.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.