A Czech SIM card and phone number: prepaid, contracts, keeping your number and roaming

A Czech phone number is one of the first things to sort out: banks, landlords and offices expect one. You can have it the day you arrive with a prepaid card, then move to a contract once you have the documents for one. This page covers both, how to keep your number when you switch, roaming, emergency calls and where to complain. It names no prices: the regulator's comparison tool, linked below, has them.

Prepaid or contract: which should I get?

A prepaid card is the quickest start. You pay for credit up front and top it up; there's no monthly bill.

• No ID needed in law. The Electronic Communications Act asks operators only to keep the data they happen to have on activated prepaid cards; it sets no duty to show ID or register.¹ Vodafone says on its own page that you need no documents to buy a new prepaid card.²
• No signing. At O2 the prepaid contract starts the moment the SIM card first connects to the network.³
• Credit can run out. Under an operator's terms, unused credit can expire, the regulator says.⁴

A contract (tarif, or paušál) has a monthly bill, but operators ask for more before they sign. Many people start on prepaid and switch to a contract, keeping the same number, once they have their residence permit card.

What do I need for a contract?

Each operator sets its own rules, and they differ. Here is what their own pages say in 2025 and 2026:

• Vodafone: a citizen of a country outside the EU shows a passport, a permanent or long-term residence card, or an employee card (only with a Czech birth number), valid for at least 6 more months, plus a second document such as a photo ID from home or a student card.² You pay a refundable deposit that depends on the services, with a higher minimum for anyone, Czech or foreign, without permanent or long-term residence in Czechia.⁵ You can sign from age 15, and a fixed-term contract from 18.²
• T-Mobile: an ID card or passport and, if you aren't a Czech citizen, a permanent or long-term residence permit. It asks only some customers for a deposit.⁶
• O2: an official identity document. If you refuse a check in the SOLUS register of debtors, O2 can ask for a deposit.⁷

The law says an operator can't set discriminatory conditions because of your nationality or where you live, unless there are objective reasons.⁸ The contract must hold your name, address and either your date of birth or a birth number, so you don't need a Czech birth number to sign.⁹

What should I check before I sign?

The law protects consumers in a few ways:

• A summary first. Before you sign, the operator must give you a free contract summary on a standard EU form, online and by phone too.¹⁰
• 24 months at most. A fixed-term contract can't run longer; if it does, it counts as an open-ended one.¹¹
• Leaving early. The operator can charge you for ending a fixed-term contract only if it ends within 3 months of signing, and then at most a twentieth of the monthly fees left, worked out from what you actually pay. A discounted phone you keep is paid off separately.¹²
• Automatic renewal. The operator must warn you at least a month before a fixed-term contract renews itself. Once it has, you can cancel at any time, free, with at most a month's notice.¹³
• Changes. The operator must tell you about changes at least a month ahead. You can then cancel free within a month, unless the change only helps you, is purely administrative or is required by law.¹⁴
• Extras. Adding a service or a phone doesn't lengthen your contract unless you agree to that explicitly.¹⁵
• Usage warnings. The operator must warn you before you reach a usage limit in your plan, and when an allowance runs out.¹⁶

The regulator says you can ask any operator to block premium-rate text messages and calls, which may be switched on by default.¹⁷

How do I keep my number when I switch?

Keeping your number when you change operator is free.¹⁸

1. Get your code. Your current operator gives you a verification code (ověřovací kód účastníka, OKU). Contracts signed since 1 April 2020 contain it; on prepaid you get it by text, email or in the operator's app or website.¹⁹
2. Apply to the new operator with the code. The new operator arranges the switch.¹⁹
3. Wait 2 working days. The switch takes 2 working days from when your old operator receives the order, and your line may be down for at most 6 hours on the day.²⁰

Your contract with the old operator ends on the day of the switch. The old operator can't stop it, but it can bill you for the part of the month you used and any agreed fee for leaving early.²¹ If you were on prepaid, ask the old operator within 30 days to refund the credit left; it can deduct its costs if your contract says so.²² And if you cancel a contract yourself, you can still take your number to another operator for at least a month afterwards.¹⁸

Can I use my phone from home here, and my Czech SIM abroad?

Within the EU, plus Iceland, Liechtenstein and Norway, you roam like at home: no extra charge on top of your domestic price. The rules run until 30 June 2032.²³ Since 1 January 2026 Ukraine and Moldova are part of the same area, for roaming between their networks and the EU's.^{24 25}

The rule is meant for travel, though. An operator can ask for proof that you live in its country or have stable links there, and after watching your use for at least 4 months it can add a roaming surcharge, which is capped.²⁶ If you live in Czechia and keep using a SIM from another country, your home operator may start charging you; a Czech number avoids that. The EU and Ukraine decision also allows exceptional limits, so check your Ukrainian operator's terms.²⁴

Which number do I call in an emergency?

Calls to the emergency numbers are free and need no credit: 112 (any emergency), 150 (fire), 155 (ambulance) and 158 (police).²⁷ 156 reaches the municipal police.²⁸

• No SIM card? Dial 112. It connects from a mobile with no SIM and no credit, as long as there's a signal from any network.²⁹
• Your language: the emergency centres can also take calls in English or German.³⁰
• Text messages: you can also text the emergency lines. A visitor whose foreign SIM is roaming in Czechia texts +420 720 000 112.³¹

Emergencies and pharmacies covers what to say when you call, and where to get help at night.

Where do I compare offers, and where do I complain?

The Czech Telecommunication Office (Český telekomunikační úřad, ČTÚ) is the regulator.

• Compare offers: its free price and quality comparison tool at srovnavac.ctu.gov.cz lists the offers operators must enter themselves.³²
• Check coverage: its coverage map shows where each network reaches, by technology.³³

To complain about a bill or a service, follow these steps:

1. Complain to the operator first, within 2 months of getting the bill or of the faulty service. On prepaid, which has no bill, the 2 months run from the day of the service. The operator must answer within a month.³⁴
2. Then go to ČTÚ. If the operator turns your complaint down or doesn't answer in time, you can lodge an objection (námitka) with ČTÚ within a month. It decides within 90 days, or 180 in complex cases, and the administrative fee is 100 Kč.³⁵
3. File it properly. Send it in writing, through a data box, by email with a recognised electronic signature, through the ČTÚ online form, or in person at a regional office. A plain email has no legal effect.³⁶

Sources

1. Electronic Communications Act (Act 127/2005 Coll.), §61(4) and §63(8). ↩ ↩²

2. Vodafone, buying a SIM card, sections on prepaid services and on foreigners, updated 25 May 2026. ↩ ↩² ↩³ ↩⁴

3. O2, general terms for the O2 prepaid service, in force from 1 July 2025, art. 1.6. ↩

4. Czech Telecommunication Office, I have a problem with credit. ↩

5. Vodafone, terms for tariff customers without a written contract, deposit paragraph. ↩

6. T-Mobile, signing a contract, documents needed in a shop, and deposits paid at activation. ↩ ↩²

7. O2, general terms, in force from 1 March 2025, arts. 3.4 and 3.5. ↩

8. Electronic Communications Act (Act 127/2005 Coll.), §61(8). ↩

9. Electronic Communications Act (Act 127/2005 Coll.), §63(8). ↩ ↩²

10. Electronic Communications Act (Act 127/2005 Coll.), §63(5) and (6). ↩

11. Electronic Communications Act (Act 127/2005 Coll.), §63b(1). ↩

12. Electronic Communications Act (Act 127/2005 Coll.), §63b(7) to (9), as amended from 1 July 2025. ↩

13. Electronic Communications Act (Act 127/2005 Coll.), §63b(3) and (4). ↩

14. Electronic Communications Act (Act 127/2005 Coll.), §63b(5). ↩

15. Electronic Communications Act (Act 127/2005 Coll.), §63c(3). ↩

16. Electronic Communications Act (Act 127/2005 Coll.), §63(9). ↩

17. Czech Telecommunication Office, I have a problem with third-party services. ↩

18. Electronic Communications Act (Act 127/2005 Coll.), §34(1) and (12). ↩ ↩²

19. Electronic Communications Act (Act 127/2005 Coll.), §34(7)(d); Czech Telecommunication Office, problems with porting a number. ↩ ↩²

20. Decree 58/2022 Coll. on number porting, §4(1) and (5). ↩

21. Electronic Communications Act (Act 127/2005 Coll.), §34(7) and §63b(11); Czech Telecommunication Office, problems with porting a number. ↩ ↩²

22. Electronic Communications Act (Act 127/2005 Coll.), §34(10). ↩

23. Regulation (EU) 2022/612 on roaming, Art. 4(1) and Art. 24; Your Europe, mobile roaming costs. ↩

24. Decision No 2/2025 of the EU-Ukraine Association Committee in Trade configuration, Art. 1 and 3, recital 10. ↩ ↩² ↩³

25. Decision No 1/2025 of the EU-Moldova Association Council, Art. 1 and 11. ↩

26. Regulation (EU) 2022/612, Art. 5(1); Implementing Regulation (EU) 2016/2286, Art. 4. ↩

27. Electronic Communications Act (Act 127/2005 Coll.), §33(1). ↩

28. Decree 117/2007 Coll. on numbering plans, annex 1, point 4.5. ↩

29. South Bohemian Fire and Rescue Service, 1 + 1 = 2, or 11 February, or 112; Czech Telecommunication Office, leaflet on special and emergency lines, updated 14 April 2025. ↩

30. Czech Telecommunication Office, leaflet on special and emergency lines, p. 2. ↩

31. Electronic Communications Act (Act 127/2005 Coll.), §33(14)(b); Decree 117/2007 Coll. on numbering plans, §26a. ↩

32. Czech Telecommunication Office, about the comparison tool; Electronic Communications Act (Act 127/2005 Coll.), §66a. ↩

33. Czech Telecommunication Office, mobile coverage map. ↩

34. Electronic Communications Act (Act 127/2005 Coll.), §64(8) to (10). ↩

35. Electronic Communications Act (Act 127/2005 Coll.), §129(1) and (3); Administrative Fees Act (Act 634/2004 Coll.), annex, item 110(d). ↩

36. Czech Telecommunication Office, which disputes ČTÚ settles. ↩

37. Czech Telecommunication Office, report on the electronic communications market in 2025, chapter 2.1.1. ↩