How to: Activate your UK Pre-Paid SIM Card

Here are the things you must know before you activate your SIM card and get connected with us. First…


Do not open your new SIM card.

Read this whole page first!

It is a mandatory condition of your purchase that you read all of the information here.

This page explains how to activate your UK Phone SIM card and gives important information about its use.

If you don’t read and understand the instructions below, your SIM card may not work properly or at all.

We do not provide post-sale support for questions answered on this page.

While we provide your SIM card, how it works is partly controlled by technical and network considerations beyond our control. These can permanently and instantly void your SIM. As they relate to factors outside our control, we cannot offer refunds or replacements related to technical and network issues.

Important points:

  1. These instructions are only for a phone SIM card, not a data SIM card. NEVER put one of our phone SIM cards in an iPad, Tablet or Hotspot device – it will be instantly cancelled by the network. If you have incorrectly purchased a phone SIM card and need a data SIM card, please contact us by email
  2. DO NOT insert the SIM card into any phone until you arrive in UK/Europe. If you do, the SIM is instantly and permanently cancelled by the network. This is completely out of our control and we cannot offer refunds or replacements if you break your SIM card by doing this.
  3. Our SIM cards only work with phones that are unlocked (also called “SIM-free phones”). We cannot unlock your phone. If you’re unsure if your phone is unlocked, please contact your network carrier. No refunds are provided under any circumstances if your SIM doesn’t work because your phone is locked.
  4. Our SIM cards only work with phones that are technically compatible. All iPhones are compatible. For other phones, you can check the phone specifications or check your phone make, model and variant at or visit and select “United Kingdom” as the country then select “3” from the carrier list. Generally speaking, your phone will be compatible if it matches one of:
    1. 4G/LTE 800MHz
    2. 4G/LTE 1800MHz
    3. 3G 2100MHz

No refunds are provided under any circumstances if your phone isn’t technically compatible (and therefore the SIM Card doesn’t work).

Once you are in Europe, you can safely activate your SIM:

Step 1: Find the size of SIM your phone needs and pop out the correct size SIM from the packaging. If you remove the smaller SIM first, the larger SIM will no longer work. If you don’t know which SIM size to use, refer to your device owner’s manual or search online for your phone’s SIM size.

Step 2: Insert the SIM card into your phone upon arrival in the UK or Europe. As mentioned above, if you insert the SIM card before you are on the ground in UK/Europe, the card is instantly and permanently voided by the network. We cannot offer a refund or a replacement in this case.

Step 3: Within a few seconds of your phone first connecting to a UK/Europe network, you’ll receive a text message saying that your SIM card is being set up. You must leave your phone switched throughout this period. You won’t be able to call, text or use data during setup.

If you’re using an iPhone, you might also get a pop-up telling you that there are new carrier settings. Accept the new carrier settings.

Step 4: Once your SIM card has been set up, you’ll soon get another text message asking you to turn your phone off and on again. Once you’ve done this your SIM card will be ready for use.

(Note: Sometimes these text messages do not appear. This is normal. If you can call, text and use data then your SIM card has been successfully activated. You do not need to contact us for confirmation.)

Step 5: If you do not have an iPhone, you may need change a certain setting on your phone. (Usually this is automatic, but sometimes it’s not). First, you may receive a text message about setting up data and picture messaging. Make the changes suggested. If, after setting up your SIM card, data isn’t working on your phone, you must now manually change your phone’s APN settings – follow these instructions.

Step 6: If you’re going to use your phone in any of the included 34 European countries, you must turn data roaming to ON in your phone’s settings.

Step 7: If you want to call or text Australian, US or Canadian numbers it will cost extra and you’ll need to add extra credit.

If you have any difficulties with the activation of your UK phone SIM card, please call Three UK as follows:

  • On your phone – call 333
  • From other UK phone – call 07782 333 333
  • A phone outside the UK – call +447782 333 333 (standard international direct dial rates apply).


One last point:

After you’ve activated your SIM card you might receive text messages from the network provider Three UK. We do not control this.

These texts might be promotional or requests that you refill/recharge your SIM card. Ignore them.

Your 30-day plan is with UK Pre-Paid SIM Card, not Three UK. There is no need to call or email us about Three UK’s texts.

Leave a Reply

Your email address will not be published. Required fields are marked *