If you’d like to keep your existing phone number, you’ll need to request a Porting Authorisation Code (PAC) from your current provider. Once you have your PAC code, simply provide it to your new network to begin the transfer process.
Getting a PAC code is easy—just text PAC to 65075, and your current provider will send it to you. The code remains valid for 30 days, so be sure to use it before it expires. If needed, you can request a new one at any time.
If your contract has ended and you’re happy with your current phone, switching to a SIM-only plan can help you save money. Be sure to make the switch early to avoid unnecessary charges and ensure a seamless transition.
The best SIM-only provider depends on what matters most to you, whether it’s coverage, speed, perks, or flexibility. Here’s a quick overview of what the UK’s four major networks offer:
Vodafone – Offers a range of SIM-only plans and pay-as-you-go options. Select Entertainment plans include access to Spotify Premium, YouTube Premium, or Amazon Prime at no extra cost.
EE – Known for having one of the UK’s widest coverage areas and the fastest mobile network speeds. Some premium SIM plans come with Inclusive Extras, offering free subscriptions to services like Apple Music, Netflix, and BT Sport.
Three – Frequently rated as the fastest 5G network in the UK. Every SIM includes access to Three+ rewards, providing exclusive offers, discounts, and early access to event tickets.
O2 – Depending on the plan, O2 offers free subscriptions to Apple Music, Disney+, Amazon Prime, or Audible. Their O2 Priority rewards program grants exclusive deals on shopping and dining, plus early access to pre-sale tickets. O2 also remains the only major UK network still offering inclusive EU roaming.
All four providers offer 1-month, 12-month, and 24-month contracts, giving you the flexibility to choose the right plan for your needs.
While the four main networks offer great SIM-only deals, smaller providers—known as Mobile Virtual Network Operators (MVNOs)—can often be a more affordable alternative. These networks operate on the infrastructure of major providers, meaning you get the same reliable coverage at a lower price.
Here are some MVNOs to consider:
Smarty – Owned by Three, Smarty offers access to the UK’s fastest 5G network, with all SIM-only plans supporting 5G at no extra cost.
Tesco Mobile – Powered by O2, Tesco Mobile delivers 99% 4G coverage across the UK and 5G connectivity in many locations. They’ve also pledged no EU roaming fees until 2026, making them a great choice for frequent travellers.
iD Mobile – A budget-friendly option using Three’s network, providing fast 5G coverage at an affordable price.
Giffgaff – Runs on O2’s network, offering broad coverage and access to an extensive range of WiFi hotspots across the UK.
Lebara – Uses Vodafone’s network, providing 5G access, international roaming, and 4G calling technology for a seamless experience.
VOXI – A Vodafone-owned provider offering competitively priced plans with unlimited social media and video streaming, helping to preserve your data allowance.
These smaller networks give you access to the same high-quality coverage as major providers, often at a more budget-friendly price.
Absolutely! Smaller networks may not be as widely recognized as the major providers, but they operate on the same infrastructure, ensuring the same level of coverage and performance.
Many MVNOs offer customer support primarily online rather than via phone, but they provide access to extensive self-service options, knowledgeable staff, and active user communities to help troubleshoot any issues.
SIM-only plans give you a set allowance of calls, texts, and data each month, but there are different options to suit your needs.
If you’re looking for a budget-friendly option, a low-cost SIM-only plan provides essential data and minutes at an affordable price. On the other hand, an unlimited data SIM allows you to stream, browse, and download without limits.
For those who prefer pay-as-you-go (PAYG), some networks offer contract-free SIMs with no credit checks—simply top up and pay for what you use. Monthly rolling PAYG plans also exist, giving you the flexibility of a contract without a long-term commitment.
There are also data-only SIMs, perfect for tablets, laptops, or portable MiFi devices, ensuring you stay connected while on the move.
SIM-only plans come in a range of contract lengths, including 30-day rolling plans, 12-month contracts, and 24-month options.
If you're happy to commit, a longer-term contract usually offers better value with lower monthly costs. However, a 30-day SIM provides greater flexibility, allowing you to switch plans or providers whenever you need.
The cost of a SIM-only plan depends on your data usage, as most deals now include unlimited calls and texts.
If you regularly stream movies, TV shows, or music on the go, you’ll need a larger data allowance—typically 60GB to 200GB per month, or even an unlimited data plan. These tend to cost £20 or more per month, depending on the provider and contract length.
For lighter phone users who mostly rely on Wi-Fi, a smaller data plan is the most cost-effective option. Entry-level SIM-only plans with 1GB to 4GB of data can cost as little as £5-6 per month.
The amount of data you need depends on how you use your phone. If you only check emails or browse the web occasionally, a 1-2GB plan should be enough.
However, if you stream music, watch videos, listen to podcasts, or use social media frequently on the go, you’ll need a larger data allowance. Options range from 10GB to 100GB, or you can opt for unlimited data for worry-free usage.
Yes! Most major networks now offer 5G SIM-only deals as standard.
All SIM cards are 5G-ready at no extra cost, so as long as you have a 5G-compatible handset, you can start using faster speeds immediately.
Where is 5G Available in the UK?
5G coverage is now available in over 100 towns and cities across the UK, including major locations such as London, Cardiff, Aberdeen, Birmingham, Belfast, Edinburgh, Manchester, Bristol, Liverpool, Glasgow, Leeds, Sheffield, Newcastle, and Nottingham.
Mobile networks are continually expanding their 5G coverage, so if your area isn’t connected yet, it’s likely to become available in the near future.
SIM cards come in three different sizes:
Most modern smartphones use nano SIMs, including any iPhone released since the iPhone 5 (2012) and most Android devices from the past decade. Standard and micro SIMs are now rarely used.
Not sure which size you need? Most networks send a 3-in-1 SIM, allowing you to pop out the correct size for your device.
What is an eSIM?
Some newer smartphones support eSIM technology, which uses a built-in chip instead of a physical SIM card. This allows you to switch providers without needing to replace your SIM, making the process faster and more convenient.
Currently, eSIMs are supported by EE, O2, Three, and Vodafone. To use one, you’ll need a compatible device, such as an iPhone XR or newer (2018 onwards) or a Samsung Galaxy S20 or newer (2020 onwards).
Whether you can cancel your SIM-only plan depends on the type of contract you have.
30-day rolling contracts can be cancelled at any time, as you’re only paying for one month at a time. While these plans offer the most flexibility, they tend to cost slightly more than longer-term contracts.
12 or 24-month contracts are harder to cancel early without paying an exit fee. This charge usually covers the remaining months of your contract.
If you're within 30 days of your contract ending or still in the 14-day cooling-off period, you can cancel without penalty.
Some networks may allow cancellations due to poor signal, but this can be difficult to prove and usually requires evidence of ongoing issues.