1. Your comprehensive guide to SIM only deals in the UK
Are you nearing the end of your mobile phone contract? Perhaps you're perfectly happy with your current handset and recoil at the thought of paying hundreds of pounds for a new one. If either of these sounds familiar, a SIM only deal could be the key to significantly reducing your monthly outgoings without sacrificing performance.
These plans have exploded in popularity, offering flexibility, value, and simplicity. But with so many networks, data allowances, and contract lengths to choose from, navigating the market can feel overwhelming. This guide will demystify the world of SIM only deals, providing you with everything you need to know to find the perfect plan for your needs and save a considerable amount of money in the process. We'll cover how to switch, what to look for in a deal, and how to ensure a smooth transition to a cheaper, more flexible mobile plan.
2. What exactly is a SIM only deal?
At its core, a SIM only deal is wonderfully straightforward. It's a package that provides you with a monthly allowance of calls, text messages, and mobile data, just like a traditional pay-monthly phone contract. The crucial difference is that the deal does not include a new handset. You are purely paying for the service you use.
Because you're not paying off the cost of a brand-new smartphone over 24 or 36 months, the monthly price is dramatically lower. This makes it an ideal choice for anyone who:
- Has come to the end of a traditional phone contract and wants to keep their existing phone.
- Prefers to buy a phone outright (either new or refurbished) and pair it with a flexible plan.
- Wants to avoid the long-term financial commitment of a handset contract.
You receive a new SIM card (or an eSIM activation code) from your chosen provider, pop it into your existing phone, and you're ready to go. It’s a simple concept that puts you in control of your mobile spending.
3. The compelling case for going SIM only
Switching to a SIM only plan can feel like a breath of fresh air after years of being tied to expensive handset contracts. The benefits are numerous and cater to a modern consumer's desire for value, flexibility, and control.
The advantages of choosing SIM only
- Significant cost savings: This is the headline benefit. Without the cost of a new device bundled in, monthly payments are a fraction of what you'd pay for a traditional contract. The savings can add up to hundreds of pounds over the course of a year, freeing up cash for other things.
- Unmatched flexibility: The SIM only market is famous for its short-term, rolling 30-day contracts. This setup is perfect if your circumstances change or if you simply don't want to be locked into a one or two-year agreement. If a better deal comes along next month, you're free to switch with minimal notice.
- A huge range of choice: Every single mobile network in the UK, from the big four to the dozens of smaller providers, offers SIM only plans. This fierce competition keeps prices low and means there's a perfect deal out there for everyone, regardless of your data needs or budget.
- Easier credit checks: Because the network isn't lending you an expensive handset, the risk for them is much lower. Consequently, the credit check for a SIM only deal is often less stringent than for a full phone contract. Many 30-day plans don't require a hard credit check at all, making them accessible to more people.
- Keep the phone you love: If your current phone still works perfectly well, why replace it? A SIM only deal allows you to continue using a device you're familiar and happy with, reducing electronic waste and saving you the hassle of setting up a new phone.
Are there any downsides?
While the benefits are clear, it's important to consider the potential drawbacks to see if SIM only is the right fit for you.
- You need your own phone: This is the most obvious point. A SIM only deal is only viable if you have a working, compatible handset.
- Your phone must be unlocked: If you originally got your phone on a contract, it might be 'locked' to that specific network. Before you can use a SIM from a new provider, you'll need to get it unlocked. We'll cover how to do this later in the guide.
- Large upfront cost for a new phone: If you do want a new phone, you'll have to buy it outright. This can mean a significant upfront expense, whereas a traditional contract spreads that cost over a long period.
For most people who already own their phone, the advantages far outweigh these considerations, making the switch a financially savvy move.
4. Getting started: your pre-switch checklist
Before you dive in and compare deals, a little bit of preparation can ensure you choose the right plan and have a seamless experience. Taking a few minutes to check these three things will pay dividends.
1. Don't overestimate your data needs
Mobile data is often the biggest variable in the price of a SIM only plan. It's tempting to opt for a huge or even unlimited data allowance "just in case," but this can lead to you overpaying for data you never use.
Recent studies and polls consistently show that the majority of UK mobile users use far less data than they think. While industry reports show average usage creeping up, many people still use under 10GB per month, with a significant portion using less than 5GB. This is because most of us spend a lot of our day connected to Wi-Fi at home or work, which doesn't use our mobile data allowance.
How to check your current usage:
- Your network's app: The easiest way is to log into your current provider's mobile app or website. There should be a clear dashboard showing your data consumption for the last few months.
- Your phone's settings: Both Android and iOS devices track mobile data usage.
- On an iPhone, go to Settings > Mobile Data and scroll down to see your usage for the "Current Period."
- On an Android phone, this is usually under Settings > Network & internet > Mobile network.
Check your usage over the last two or three months to get a realistic average. You might be surprised at how little you actually need. Choosing a 10GB plan instead of a 100GB plan could halve your monthly bill.
2. Ensure your phone is unlocked
If you plan to switch to a different mobile network, your phone must be unlocked. A locked phone will only accept a SIM card from the network it was originally purchased from.
The good news is that under Ofcom regulations, all mobile phones sold in the UK since December 2021 must be sold unlocked. If you bought your phone after this date, you shouldn't have any issues.
If your phone is older, it might be locked. Here's how to check:
- The simple test: The easiest way is to borrow a SIM card from a friend or family member who is on a different network. Turn off your phone, insert their SIM, and turn it back on. If you can make a call or see the new network's name at the top of the screen, your phone is unlocked.
- Check your phone's settings: On some iPhones, you can go to Settings > General > About. Scroll down to find "Network Provider Lock." If it says "No SIM restrictions," your phone is unlocked. This method isn't always available on Android devices.
What if my phone is locked?
Don't worry, unlocking your phone is usually straightforward and often free. If you are out of contract with your old provider, they are legally obliged to provide you with the unlocking code for free. If you're still in contract, they might charge a small administrative fee. Simply contact your current provider's customer service, and they will guide you through the process.
3. Check the network coverage in your area
There's no point in grabbing a fantastic deal if you can't get a reliable signal at home, work, or on your daily commute. While UK network coverage is generally excellent, there can be blackspots.
All mobile providers in the UK use the infrastructure of one of four main networks: EE, O2, Three, and Vodafone. Smaller providers, often called Mobile Virtual Network Operators (MVNOs), piggyback on one of these core networks. For example, Giffgaff uses O2's network, while Smarty uses Three's. This means that if you get good O2 coverage, you'll also get good Giffgaff coverage.
Before committing, use a coverage checker tool. Ofcom, the UK's communications regulator, has an official, independent checker on its website. You can input your postcode to see the predicted indoor and outdoor signal strength for calls, 4G, and 5G data for all four main networks. This is an invaluable step to avoid disappointment later on.
5. The simple guide to switching networks and keeping your number
Thanks to Ofcom's "Text-to-Switch" initiative, the days of awkward phone calls and hard-sell tactics from your old provider are over. The process is now refreshingly simple, fast, and entirely managed via text message.
Step 1: Request your switching code by text
You only need to send one free text message to get the code you need. The code you request depends on whether you want to keep your existing mobile number.
- To keep your number, request a PAC: Text the word PAC to 65075.
- To get a new number, request a STAC: Text the word STAC to 75075.
A PAC (Porting Authorisation Code) tells your new provider to transfer your existing number over. A STAC (Service Termination Authorisation Code) tells them to end your old service and provide you with a new number.
Within a minute, you'll receive a text message back containing your code. This reply must also include important information, such as any early termination fees if you're still in contract, or details of any outstanding balance.
If you're not sure about your contract status, you can text INFO to 85075 to get these details without requesting a switching code.
Step 2: Order your new SIM only deal
Now that you have your code, you can go ahead and find the best SIM only deal for you. Once you've chosen your new network and plan, sign up on their website. They will send you a new SIM card in the post (this can take a few days).
Step 3: Give the code to your new provider
Your PAC or STAC is valid for 30 days. Once your new SIM card arrives and you have activated it, you need to give the code to your new network.
Most providers have a simple online form on their website where you can submit your code and the phone number you wish to port. You can usually find this by searching for "transfer my number" or similar on their site.
Step 4: The switch happens automatically
Once you've submitted your code, the magic happens behind the scenes. The switch will be completed within one working day. You don't need to contact your old provider again; your new provider handles everything. Your old service will be cancelled automatically as soon as your number moves across.
One of the best parts of this new system is that you can no longer be charged for a notice period beyond the switching day. This puts an end to the frustrating practice of paying for both your old and new service at the same time.
6. Choosing your perfect plan
With the groundwork done, you can focus on the specifics of the deal itself. Consider these factors to narrow down the vast array of options.
Contract length: finding the right balance
SIM only deals are typically available in three main contract lengths, each with its own pros and cons.
- 30-day rolling contracts: These offer maximum flexibility. You pay on a month-by-month basis and can cancel or change your plan with just 30 days' notice. They are perfect if you're not sure how much data you'll need, if you anticipate your circumstances changing, or if you simply want the freedom to jump on a better deal whenever one appears. The monthly cost may be slightly higher than a longer contract, but the freedom is often worth it.
- 12-month contracts: This is a popular middle ground. By committing for a year, you'll often get a better monthly price or a more generous data allowance than on a 30-day plan. It's a great option if you're happy with your chosen network and want to lock in a good price for a reasonable period without a very long-term commitment.
- 24-month contracts: For those who value stability and the lowest possible monthly price, a two-year contract can be the most cost-effective choice. Networks reward this longer commitment with their very best rates. This is ideal if you've found a network with excellent coverage that you're happy to stick with for the long haul.
Big networks vs. smaller providers
As mentioned earlier, you have a choice between the four major networks (EE, O2, Three, Vodafone) and a host of smaller MVNOs that use their infrastructure (like Smarty, Giffgaff, Voxi, Tesco Mobile, and many more).
- Major networks: Often attract customers with extra perks, such as O2's Priority rewards scheme, Vodafone's VeryMe offers, or inclusive subscriptions to services like Apple Music or BT Sport on premium EE plans. They also have physical stores and extensive telephone customer service centres.
- Smaller providers (MVNOs): Tend to focus on one thing: exceptional value. They often strip back the fancy extras and focus on providing generous data allowances for a very low monthly cost. Customer service is typically online-only, via web chat or community forums. Don't be concerned about their quality of service; because they use the same infrastructure as the major networks, their signal strength and data speeds are comparable.
There's no right or wrong answer here. The best choice depends on whether you prioritise perks and extensive support or just want the lowest possible price for your monthly allowance.
7. Important things to watch out for
While the process is generally smooth, there are a couple of final points to be aware of when you apply for a new plan.
Credit checks
Most networks will perform a credit check when you apply for a pay-monthly SIM only deal, even a 12 or 24-month one. This is usually a 'soft' search that won't impact your credit score, but it's still a factor. If you have a poor credit history, you may find it easier to be accepted for a 30-day rolling contract, as the financial risk to the provider is much lower. Some networks that specialise in flexible plans may not perform a credit check at all for these deals.
Annual price rises
It's crucial to be aware that almost all major network providers include a clause in their terms and conditions that allows them to increase your monthly price each year. This is usually done in April and is typically linked to the rate of inflation (either the Consumer Price Index or Retail Price Index) plus an additional percentage. These price rises can be significant, so it's wise to factor this in when comparing deals, especially for longer 24-month contracts. If a price rise is written into the contract you agree to, you do not have the right to leave penalty-free.
8. Frequently asked questions
Q: What type of SIM card will I need for my phone?
A: There are three physical SIM sizes: standard, micro, and nano. However, almost all modern smartphones released in the last decade use the smallest size, the nano SIM. You don't need to worry about which one to order, as virtually all networks now send out a "3-in-1" or "combi" SIM. This is a standard-sized card with the micro and nano sizes pre-cut, allowing you to simply pop out the one that fits your device. Some newer phones also support eSIMs, which are digital SIMs that can be activated via a QR code.
Q: Can I get a SIM only deal for my tablet or mobile Wi-Fi device?
A: Yes, absolutely. Many networks offer "data-only" SIMs, which are designed specifically for these devices. They come with a data allowance but typically don't include any minutes or texts, making them cheaper than a standard phone SIM.
Q: What should I do with my old SIM card after I switch?
A: Your old SIM card can store contacts and other personal information. Once your number has been successfully transferred and your new SIM is working, it's best to securely destroy your old SIM card. The simplest way is to cut it in half with a pair of scissors, making sure to cut through the metal chip.
Q: Will a SIM only deal improve my credit rating?
A: Potentially, yes. A pay-monthly SIM only contract is a form of credit agreement. By paying your bill in full and on time every month, you demonstrate responsible financial behaviour, which can have a positive impact on your credit score over time. Conversely, missing payments will have a negative effect.
