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Do all Phones Work with UK Sim Cards? What to Know Before Visiting.

When travelling to the United Kingdom, you may consider using a local SIM card from the UK. If you have a phone with an interchangeable SIM card, then you should take advantage of a local SIM card’s benefits.

Do all phones work with UK Sim cards? Not all phones work with SIM cards from the United Kingdom. Some phones operate on a network called CDMA which will prevent you from being able to use a foreign card. If your phone operates on GSM, then you can use a UK SIM card after you have the phone unlocked.

What to know before visiting? It is important for travellers to know whether your phone is compatible with using a UK SIM card and where to find them. If you don’t have a compatible phone, it is good to know what other options are available.

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There’s a lot of avenues for you to take to avoid the hassles of using your phone overseas. If you have the right phone for it, travelling the world with your mobile device can be a breeze. Once you know, you’ll be armed with a better understanding of your phone and how to travel with it.

Taking Your Mobile Phone to the United Kingdom

You can take your phone with you when you travel to the UK but using your mobile phone while you’re in the UK can be costly from roaming charges. If you don’t want any unexpected bills when you return home, then it might be wise to take advantage of a local SIM card to avoid such fees.

If your phone is compatible with a different card, then there are SIM cards set up as a pay-as-you-go system. You can buy an initial large sum of data, voice, and text which you plan to use the entire time, or you can add more data as you go.

If your phone comes from Canada or Australia, then your phone likely runs on GSM, but if you’re from the United States you may have a phone which runs on a different network than those internationally. Some companies out of the US, such as Verizon and Sprint, run their phones on the CDMA network which makes them unable to use a local SIM card.


The reason certain phones don’t work with other SIM cards is that they use a system called CDMA which stands for Code Division Multiple Access and they don’t even use SIM cards to operate. Phones which do communicate using SIM cards are working on a system called Global Systems for Mobile Communication or GSM.

They are both ways to access radio channels and both compress multiple calls into one radio wave. The reasons for using one network or the other was a choice for providers while some companies saw faster speeds and response times on CDMA, the others wanted the wider use by choosing GSM.

The difference between these two is how they communicate with each other. A CDMA phone communicates with specific coded segments for talking. So, the receiver’s phone only takes out its portion of the coded segments. The benefits for phones on CDMA are:

  • Increased immunity to interference
  • High-speed internet for faster data

GSM is a time division system, so calls take turns on a radio wave, but the receiver only hears their time slot. There are a lot of claims that GSM isn’t as responsive or as fast as CDMA, because most of them still connect to older 3G networks. Having a GSM phone means:

  • Can be unlocked
  • A higher percentage of the world is running on the network
  • Can easily switch carriers, local or international

The Challenge of Locked Mobile Phones

Cell service providers have the ability to lock a phone to their network when the service is shut down. When a phone is locked, many of the features are disabled and the phone cannot use a SIM card from another provider.

The phone is locked by having a code on it which enables the phone only to use the provided network, but if the phone is unlocked it can accept and use SIM cards for other networks. In 2017, Canada passed a law banning mobile companies from locking phones.

If you find yourself to be a tech-savvy individual, then there are videos on the internet which guide you through the process to unlock your phone. Some companies will unlock the phones for you, but if not, a third party out of the UK can unlock it, usually at the cost of purchasing their SIM cards.

United Kingdom’s Wireless Service Providers

Any SIM card purchased in the United Kingdom will be considered a UK SIM card. This encompasses England, Wales, Scotland, and Northern Ireland.

There are many popular providers to choose from:

  • EE Limited
  • Vodafone
  • 02
  • Three UK
  • Sky Mobile
  • Giffgaff
  • Virgin Media

These have been ranked as the best working mobile networks in the UK. Each offers competitive rates and the highest quality in data and voice throughout the United Kingdom, but for precise details, you can learn more.

Using a local UK card will work in most other countries in Europe, so if you plan to take a trip to France or any nearby countries, you can take your phone with you and not worry about any additional charges. Much of the world runs on GSM, so you always have the option to use the local SIM card of wherever you’re travelling to.

Vodafone stand in the airport
Vodafone stand in the airport

Prepaid Cards and Knowing your Usage

If you’re only visiting the UK, then you can purchase one of the SIM cards with prepaid data and voice. It is important to know how much data you’re going to need when you’re not planning on using a Wi-Fi connection.

The Sim cards can be bought with as little a 2GB and many offer unlimited data use for a certain period. Much of these pre-paid plans offer unlimited talk and texts, but each SIM card only lasts for an extensive amount of time such as 30 or 90 days.

If your planning on travelling outside of the cities and towns of the UK, then it is recommended to go for a high amount of data since you may need it for travel directions or information. For cities, you may not need such a high amount as there are ample times to connect with a business or hotel’s internet.

What Happens When You Take Out Your SIM Card?

It is best to take a SIM card out when the phone is turned off to avoid any possible glitches or software malfunctions. When your phone doesn’t have a SIM card in it:

  • You will not be able to make or receive any phone calls
  • You can’t access the internet without Wi-Fi
  • You can still make emergency calls

Taking your SIM card out will not damage your phone but for these reasons, it’s good to keep your card in your phone until you have another to switch out.

When Visiting

UK SIM cards can’t be purchased outside of the country unless you purchase it online. Buying online will save you time and allow you to have already the SIM card ready when you get to your destination. However, if you don’t purchase online, you can find them for sale in airports, some gas stations, and every mobile phone store.

If your phone isn’t compatible for a local SIM card, then you can rent Wi-Fi packs which create a wireless hotspot. While using local internet you can utilize apps such as WhatsApp or Skype to make any necessary international calls. Many phone shops in the UK also offer disposable phones which work similarly to the pay-as-you-go SIM cards and can be recycled after use.

More London Articles

If you are visiting London you may want to how to Get internet and Wi-Fi in London, read this link. If you run out of battery while exploring the city make sure you read where can you charge your phone in London.

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Hi, I'm Kat, an Australian that moved to London in 2013 to start a new adventure. What a roller-coaster that was! I love helping others move to the UK and people explore the world! I’d be honoured if you’d say, “Thanks!” with a £3 coffee on Ko-fi.

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