Before you start

Passport for a prepaid SIM
OIB and residence permit for postpaid
A Croatian bank account for direct debit on most contracts
Landlord permission for any installation

Step-by-step

1
Buy a prepaid SIM on arrival
All three operators sell prepaid packs in shops, at the airport and in kiosks. Registration against a passport is required. This covers the weeks before the OIB and bank account exist.
In personWho: YouDay 1
2
Move to postpaid once the OIB is in hand
Postpaid plans want the OIB, a residence permit and usually a Croatian bank account for direct debit. They are cheaper per gigabyte and often bundle home internet and television.
In personWho: You
3
Ask which operators serve the building — and whether it is under reconstruction
Croatian buildings are served by whichever operators have installed equipment. In Zagreb there is a second question: a building in the post-earthquake reconstruction programme may have works that affect risers, cabling and installation scheduling. Ask both.
In personWho: You
4
Expect fibre in the newer districts and mixed infrastructure in the old centre
Novi Zagreb and the newer parts of Trešnjevka and Vrbani are well fibred. The Lower Town's nineteenth and early twentieth century blocks are a mixed picture, made more so by ongoing renovation works.
OnlineWho: You
5
Use EU roaming freely, but check Bosnia and Serbia
Croatian plans include EU roaming, so Slovenia, Hungary, Austria and Italy behave domestically. Bosnia and Herzegovina and Serbia are not in the EU and are charged differently — a relevant point given how close both borders are.
Mobile appWho: You
6
Port your number when switching
Croatia operates number portability. Never cancel the old contract before the port completes.
In personWho: You

Documents you’ll need

Passport for prepaid registration
OIB and residence permit for postpaid
Croatian bank details for direct debit
Landlord permission for installation

Things most newcomers don’t know

In Zagreb, 'is the building under reconstruction' is a broadband question as well as a housing one.

The post-earthquake reconstruction programme is still running with a 2030 target, and works on a building can involve scaffolding, facade removal, riser access and, in some cases, temporary evacuation. That affects whether an operator can install, when they can install, and whether an existing connection survives the renovation. Ask about the building's status before signing a broadband contract with a minimum term.

Source: Ministry of Physical Planning, Construction and State Assets

The land borders make roaming a two-tier question here in a way it is not in Prague or Warsaw.

Zagreb is under two hours from Slovenia, three from Hungary and about the same from Bosnia and Herzegovina and Serbia. The first two are EU and roam at domestic rates; the last two are not and do not. A weekend in Sarajevo or Belgrade on an unmanaged Croatian plan produces a bill that a weekend in Ljubljana does not.

Source: HAKOM

Prepaid SIMs are registered, so the anonymous option does not exist.

Croatian operators register prepaid SIMs against identity documents. A passport suffices on arrival, so this is no obstacle, but the anonymous prepaid SIM described in older guides is gone. The upside is that a lost SIM can be blocked and the number recovered.

Source: HAKOM

Bundling is the sensible default and standalone broadband is poor value.

Croatian operators price combined mobile, broadband and television packages well below the sum of the parts, and the discount is substantial rather than token. Anyone signing a standalone broadband contract alongside a separate mobile plan is usually paying more than they need to. Ask for the bundle price explicitly.

Source: community-reported

Common mistakes to avoid

Signing a broadband contract without checking whether the building is due for reconstruction works.
Assuming Bosnia and Serbia roam at EU rates because they are neighbours.
Attempting a postpaid contract before the OIB exists.
Taking a standalone broadband deal instead of the bundle.
Cancelling an old contract before the number port completes.

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