How to block or reactivate your SIM card and mobile number

Have you lost your SIM card or mobile phone? Act quickly and block your SIM as soon as you notice that it is missing. This helps protect your mobile connection from unauthorized use.

In this article, we explain how to block and, where possible, reactivate your SIM card or mobile number. Please note: logging in to the relevant o2 online service is required for these options.

I have a mobile contract

Block or unblock your SIM card

If your SIM card is lost or stolen, you can block it directly via the o2 customer portal:

👉 Block your SIM

If you find your SIM card again or it is returned to you, please contact o2 Customer Service to have the SIM card unblocked again.

Good to know: Block your SIM as soon as you notice that it is missing. This prevents your SIM from being used by someone else.

Block or unblock specific call functions

Instead of blocking the entire SIM card, you can also restrict certain call functions for your mobile number.

The following options are available:

• Block all incoming calls
• Block all incoming calls while abroad
• Block all outgoing calls
• Block all outgoing calls while abroad
• Block calls to 0900 premium-rate numbers

You can manage these restrictions here:

👉 Manage call barring

Changes are usually applied within around five minutes after you submit the request.

Are there any charges?

Charges may apply when blocking your SIM card or mobile number. You can find the applicable fees in the current o2 price lists.

In certain circumstances, o2 is also entitled to block your SIM card in accordance with the applicable terms and conditions. A fee may be charged in such cases.

I am an o2 Prepaid customer

If you use an o2 Prepaid SIM, please contact o2 Customer Service for Prepaid to have your SIM card blocked.

Need help?

If you are unsure which type of block you need, or if you cannot access the relevant online service, you can also contact o2 Customer Service.

Quick overview