Setting up your phone & SIM.

Here you can find out how to set up your phone and SIM so that you can start making calls, sending texts and using the internet.

How you set up your phone and SIM will depend on whether you've bought the phone new from Three, or if it's an old phone or one you've bought new from a different network operator.

Setting up a new Three phone and SIM.

If you’ve bought a Three Pay As You Go phone with a SIM, it'll be ready to use as soon as you turn it on. You’ll then need to follow the steps below to activate your SIM. It'll come with a preloaded top-up or Add-on.

For help setting up your phone, go to our device support pages and select your phone. From there you'll be able to find out how to set up email, transfer your contacts from your old phone to your new one and get started making calls and sending text messages. You may also want to transfer your current phone number onto your new SIM card.

Device support.

Transfer your number.

Setting up a new SIM on a phone that isn't from Three.

If you’re using a Pay As You Go SIM in a phone that you didn’t buy from us, you’ll need to make sure it’ll work in your phone:

  • Our SIMs are only compatible with 3G or 4G phones, so your SIM won’t work if you try and put it in an older phone. To check if your unlocked phone is at least 3G, text Mobile to 78333. You won’t be charged for this service.
  • If you’re using a phone from another network, you might need to get it unlocked before you can use a Three SIM. Unlocked phones work with any SIM card, so once you’ve unlocked a phone you can move from one network to another.
  • You’ll then need to follow the steps below to activate your SIM. You may also want to transfer your current phone number onto your new SIM card.

Unlock your phone.

Transfer your number.

Activating your SIM.

Once you’ve made sure your phone is compatible, follow these steps to activate your SIM:

  1. Insert your SIM into your phone and switch it on. You may have a new Trio SIM or a regular single SIM. Please see the link below for more details.
  2. We'll text you to let you know we've started activating your SIM. Make sure you keep your phone switched on while we connect you to the Three network. This should only take about 30 minutes but during busy periods it may take longer.
  3. We’ll send you a second text telling you to turn your phone off and on again.
  4. Your SIM will be activated when you restart your phone. We’ll confirm this with another text.

If you're having any problems activating your SIM, let us know using Live chat and we'll get it sorted for you.

Please remember that if your phone is 2G or hasn’t been unlocked then we won’t be able to help you. You’ll need to visit your phone manufacturer's website.

Trio SIM.

Changing your settings and topping up.

  • You may need to change some settings on your phone to make sure you get the best possible experience and have access to the internet.
  • Once you’ve activated your phone, you may need to top-up*, which adds money to your account balance as credit. You can then use that credit to make calls, send messages and use the internet. Top-up credit never expires.
  • If you use your phone a lot, you can get extra value by using your credit to buy an Add-on, giving you more texts, minutes or data.
  • Once your credit runs out, you’ll need to top-up again to keep on making calls, sending messages and using the internet.

*If you’ve bought a new phone and SIM from Three, your phone will already be topped up with credit.

Help changing settings.


How Add-ons work.

More Pay As You Go help.

Getting started
Topping up
Your tariffs and Add-ons