Before you start

A valid passport or national ID, physically required and recorded at the point of sale for any SIM including prepaid
An unlocked phone or an eSIM-capable device
For postpaid or home internet: an AFM, a Thessaloniki address and usually a Greek or EU IBAN

Step-by-step

1
Start prepaid unless you already have an AFM
A prepaid SIM (καρτοκινητό) needs only your passport and can be topped up with monthly bundles indefinitely. A postpaid contract needs the AFM, an address and a bank account, and locks you into 12 or 24 months. Since the AFM is week one at the earliest, prepaid is the sensible first move.
In personWho: YouSame day
2
Buy and register the SIM in a carrier shop
Any Cosmote, Vodafone or Nova store in the centre will do it. The agent records your ID against the SIM on the spot, which is legally required and takes a few minutes. eSIM is available from all three, which is worth asking for if you want to keep your home number active alongside.
In personWho: You15–30 minutes
3
Top up a monthly bundle through the app
Recharge through the carrier app, online, at kiosks or in supermarkets, then activate a bundle covering data, minutes and EU roaming. Compare the bundles rather than taking the one the shop suggests; the differences between them are larger than the differences between networks.
Mobile appWho: You
4
Move to postpaid once you have the AFM and a bank account
A contract is cheaper per gigabyte and bundles with home internet and television, but it needs the AFM, a Greek address and usually a direct debit. Do it when the paperwork is in place, not before.
In personWho: You
5
Sort home internet, and ask what the building already has
Fibre coverage in Thessaloniki has expanded quickly but is uneven, and in an older apartment block what actually reaches your flat may depend on what the building's owners' association has permitted. Ask the landlord to name the provider and connection type that is physically installed, rather than relying on a coverage checker's theoretical answer.
OnlineWho: You
6
Keep your number when you switch
Number portability between Greek operators is a regulated right and takes a few working days. Never cancel the old service first — request the port and let the new operator handle it.
In personWho: You

Documents you’ll need

Passport or national ID, required for every SIM including prepaid
AFM, a Thessaloniki address and a bank IBAN, for postpaid or home internet
Landlord's consent, sometimes needed for a new installation in a shared building

Things most newcomers don’t know

Every Greek SIM is registered to an identity document, including prepaid.

This surprises people arriving from the UK, where no registration exists at all. In Greece the shop records your passport against the SIM at the point of sale — it is legally required. Practically it means you cannot buy a SIM from a vending machine or a stranger, and you must carry the passport to the shop rather than a photograph of it.

Source: EETT — Greek telecommunications regulator

Prepaid first, because postpaid needs the AFM you do not have yet.

A contract requires the tax number, a Greek address and usually a direct debit from a Greek account, none of which exist in your first week. Prepaid needs only the passport. Newcomers who try to go straight to a contract lose a fortnight and end up with no working number in exactly the weeks they need one for bank verification and appointment systems.

Source: carrier terms; community-reported

In an older block, ask what is installed rather than what is available.

Coverage maps report what an operator could theoretically serve at the address. In a mid-century Thessaloniki apartment building, whether fibre actually reaches your flat depends on what the owners' association allowed and what was physically run into the riser. Get the landlord to name the provider and connection type before you sign, not after.

Source: community-reported

EU roaming buys you time to choose properly.

Arriving from another EU country, your existing SIM works here at domestic rates under roam-like-at-home. That means you can compare Greek bundles once you know what you actually use, rather than buying whatever the airport shop is promoting in your first hour.

Source: EU roam-like-at-home rules

Common mistakes to avoid

Turning up to buy a SIM without a physical passport — a photograph will not do.
Trying to sign a postpaid contract before you have an AFM and a Greek bank account.
Trusting a coverage checker instead of asking what is physically installed in the building.
Cancelling your old service before requesting the number port.
Taking the bundle the shop suggests without comparing the alternatives.

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

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