Before you start

Passport or eID for SIM registration
A Belgian address for fixed broadband
A Belgian bank account for direct debit on most postpaid plans
An unlocked or eSIM-capable handset

Step-by-step

1
Buy a prepaid SIM on arrival and register it
Sold in supermarkets and phone shops and usable immediately, but identification is legally required and an unregistered card is deactivated. You can register with a passport before you have an eID, so this is not blocked by the commune queue.
In personWho: YouDay 1
2
Compare the resellers before signing with the big three
Mobile Vikings, hey!, Scarlet and others run on the Proximus, Orange and Telenet networks at much lower prices. Coverage is identical because the towers are the same. The flagship bundles earn their premium mainly when you want mobile and fixed together.
OnlineWho: You
3
Use the BIPT comparison tool
The federal regulator publishes an independent comparison of mobile and fixed offers. It is the only neutral one — commercial comparison sites take commission — and it exists precisely because Belgian bundle pricing is deliberately hard to read.
OnlineWho: You
4
Establish whose name the connection in a shared house is in
In a house of kots the internet is often included in the charges and contracted by the landlord, sometimes on a consumer line shared among eight people. That is fine for browsing and poor for anything else, and you cannot fix it because the contract is not yours. Ask before signing: is the line included, whose name is on it, what speed is contracted, and may you take your own line if it is not enough?
OnlineWho: You
5
Switch operators with Easy Switch
Belgium's Easy Switch process makes the incoming operator handle the migration and keeps your number with no gap in service. Cancelling the old contract first is the standard mistake and leaves you offline for a week.
OnlineWho: You
6
Book the installation slot early, and avoid September
Fixed-line activation runs one to three weeks out and often needs someone at home. In a city where tens of thousands of students move in over the same fortnight, September is the worst possible time to need an engineer. Arrange a mobile data fallback rather than assuming the line will be live on move-in day.
OnlineWho: You1–3 weeks

Documents you’ll need

Passport or eID for SIM registration
Proof of address for fixed-line installation
Belgian bank account details for direct debit
Landlord permission where cabling work is needed, and in a shared house the landlord's agreement to a second line

Things most newcomers don’t know

Anonymous prepaid SIMs were abolished in 2017 and an unregistered card stops working.

Belgian law requires every prepaid card to be tied to an identified holder. You can register with a passport before you have an eID, so this does not block you on arrival — but skipping it does. People who buy a SIM for a partner or a visiting relative and never register it lose both the number and the credit, with no retrospective reactivation.

Source: BIPT

You can walk away from a Belgian telecom contract after six months, penalty-free.

Consumer rules let residential customers end mobile and internet contracts at any point once six months have elapsed, with no early-termination charge. That matters more here than in most cities: a great many residents are on nine-month student leases or one-year research contracts, and the six-month rule means a twelve- or twenty-four-month bundle is not the trap it appears to be. Providers do not volunteer this.

Source: BIPT

The resellers use the same towers as the operators charging several times more.

Mobile Vikings, hey!, Scarlet and similar buy wholesale capacity on the Proximus, Orange and Telenet networks. Coverage and speed belong to the infrastructure, not the brand. Belgian mobile prices have been repeatedly flagged as high in EU comparisons, and the gap between a flagship bundle and an equivalent reseller plan justifies an hour of comparison in week one.

Source: BIPT

A shared house's included internet is a contract you have no rights under.

In kot accommodation the line is frequently the landlord's, shared between every room, and included in the charges. You cannot see the contracted speed, you cannot escalate a fault, you cannot switch, and the six-month exit rule protects the account holder rather than you. If your work depends on the connection — a doctoral researcher pushing datasets, anyone doing video calls all day — establish before signing whether you may install your own line, and get the answer in writing.

Source: community-reported

Common mistakes to avoid

Buying a prepaid SIM and never completing the mandatory registration.
Signing a flagship bundle without checking the resellers on the same network.
Relying on a shared house's included internet for work without checking what it actually is.
Cancelling the old contract yourself instead of using Easy Switch, and losing the number.
Needing an installation engineer in September, when the whole student city is moving in.

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