Three is a well-known mobile network provider of SIM cards in the United Kingdom and Ireland that demands a quick online activation. The procedure only requires a few specific bits of information the user can easily access after the SIM arrives at their doorstep or the nearest store. Moreover, the carrier has neat Customer Service and, as a leader in the area, hundreds of thousands of satisfied users who can advise you. We commend your decision to gain access to 99% of UK coverage, a strong presence in Ireland, and a superfast 5G network. Thus, we’ll show you how to activate a Three SIM card.
Note. Although Three is renowned for offering cellular and other services, we’ll focus on regular users. That’s because business plans change frequently, and the carrier is known to adhere to different business needs. Therefore, the activation procedure may vary or be nonexistent.
Activate a Three UK SIM card on their website
Using the official website is the primary method of activation of SIM cards provided by Three United Kingdom. Although the carrier has a great network penetration in the United Kingdom, they don’t have physical stores everywhere. Additionally, they focus on SIM-only plans, pay-as-you-go SIMs, and pay monthly SIM cards. Users don’t need to sign long contracts for postpaid SIMs (although they can) or wait for shipping devices such as phones or tablets. Consequently, the carrier can afford to deliver free SIM cards or at least charge a nominal price.
With that said, after you make an online order with your details, and the Three SIM card for the UK arrives, you can activate it this way:
- Head to the Three UK SIM Card Activation page.
- You will now see the basic instructions. In short, insert the new SIM card if you can, but don’t remove the old SIM card if you’re switching carriers until you get the notification or wait the required time.
- Navigate to the Enter your Three number. field. Enter the mobile phone number for the SIM you received without spaces or special characters.
- Fill the Your new 19-digit SIM number (ICCID). field with the ICCID number. You can find it on the back of the SIM card package you got.
- Click the Submit button. Await a sign such as a network signal that stops working on the old SIM, or the signal appearing on the new one. Carrier promises that happens within two hours.
Note that Three UK only supports 3G, 4G, and 5G devices at the time of writing. You can text Mobile to 78333 from your device to get a free network type check. Also, despite activation, depending on your plan, you may have to recharge a Three SIM before you can do anything.
Activation when buying a device with a SIM card from Three UK
If you purchase a device from Three UK, the procedure is a tad different and a lot easier. Both will ship at one, and sometimes the carrier even inserts the SIM card if requested. Activating your Three UK SIM card with their device works like this:
- Insert the SIM inside the device if it isn’t.
- Turn the device on.
- Enter your PIN (Personal Identification Number) and get to the home screen. You’ll get an SMS notifying you that your connection was detected and that the activation began.
- After 30 minutes or so (under busy periods that can take 2 hours or more), you receive a second text instructing you to turn your device off.
- After you power your device on, the SIM will be activated. A third SMS will confirm that.
Use the official website for activating a Three Ireland SIM card
Unsurprisingly, Three keeps their websites, services, and activation procedure as close as possible between the two countries they operate in. Therefore, you can follow these steps to activate your SIM card from Three IE:
- Visit the Three Ireland Activate My SIM page.
- Follow the same guidelines we described above. Type your mobile phone number for the Three SIM under Enter your mobile number:
- Click the Get Started button.
- Follow the few short instructions that include typing your ICCID as demonstrated in step 4 of the first method.
- Insert the SIM and wait for the cellular signal icon to appear in the top corner of the notification bar.
Contact Three Customer Support
Our activation guides customarily go over instructions on what to do when things turn sour. Consequently, we will present several ways to get in touch with Three based on the country.
Contacting Three UK
You can reach out to the United Kingdom brand of Three in these ways:
- Web chat — Visit the Three UK Contact page and begin chatting under Chat to us. Available 8 AM-10 PM Monday-Friday, 9 AM-8 PM Saturday and Sunday.
- Calling — Dial Three UK on 333 (from their number), 0333 338 1001 (via any number in the country), or +44 7782 333 333 (internationally).
- Social media — Message them on Instagram, Facebook, and Twitter (@threeUK).
Reaching out to Three IE
Getting in touch with Three Ireland is possible via:
- The My3 application — Download the My3 app on Google Play Store or Apple App Store. When you log in, tap the Chat option in the bottom menu.
- Live chat — Use the Three Message Us service. Support bot available 24/7, with live agents present 7 days a week from 7 AM to midnight.
- Forum — Three IE has a forum named Community (
community.three.ie) with fellow users and their experts answering questions.
- Calling — Dial 1913 for free from a Three number (8 AM-8 PM Monday-Friday, 09 AM-06 PM Saturday-Sunday).
- Email — Email them at