Reading time: 6 minutes | Posted: 16th July 2023
This is a very commonly asked question, one that we aim to answer in this guide.
Firstly Sim Cards come in all shapes and sizes but the specific SIM Card required for your phone, will not impact the deal you can choose.
Let's dig into what a SIM Card is and what the different sizes are;
What is a SIM card?
A "Subscriber Identity Module" or SIM card is a tiny microchip that allows your phone to connect to a mobile network to make and receive calls, send text messages, and use mobile data. Without a SIM card, your phone would not function as it should.
SIM cards hold a lot of important information about your phone, like your phone number, network provider, and account details. They also have a unique identification number that helps your phone connect to the mobile network and logs your device usage, such as minutes and texts, so you always know how much data you have used.
Every mobile phone needs a SIM card – it is essential to ensure your phone operates properly.
What are the UK SIM card sizes?
SIM cards come in three different sizes in the UK:
- Standard: 25 x 15mm
- Micro: 15 x 12mm
- Nano: 12.3 x 8.8mm
Standard SIM card:
Standard SIM cards have been around the longest. They are the biggest of the three sizes, measuring a whopping 25mm x 15mm. These days, they are not as common as they used to be, but they are still the most compatible choice for older handsets or less high-tech models with more space inside for hardware.
If you have a vintage phone or an older model you simply cannot part with; you will probably need a standard SIM card. But if you are into buying newer models as they are released, you may need a micro or nano SIM card.
Micro SIM card:
Micro SIM cards are smaller than standard SIM cards but not as small as nano SIM cards. Micro SIM cards were first introduced in 2003 and became more widely used after being built into the iPhone 4.
Micro SIM cards are becoming increasingly obsolete as manufacturers favour smaller nano SIM cards. However, if you have a phone that uses a micro SIM card, plenty of micro SIM cards are still available, and they are still compatible with most phones.
Nano SIM card:
Nano SIM cards are the babies of the SIM card world. They are so small they are practically microscopic! Measuring just 12.3mm x 8.8mm, nano SIM cards are the most commonly used SIM type in modern smartphone releases. First launched in 2012, they quickly became the standard for new phones.
With hardly any plastic border around the chip itself, it's hard to imagine SIM cards getting any smaller than this. But who knows, we may have nano-nano SIM cards in the future
What is an eSIM and how do I get one?
eSIMs, or embedded SIMs, have been around for over a decade, but their recent surge in popularity has brought them to the forefront of mobile connectivity. Unlike traditional physical SIM cards, eSIMs are tiny chips embedded directly within a device, eliminating the need for a separate card.
Many eSIM plans can be easily purchased online and activated through a simple QR code scan. This removes the hassle of waiting for a physical card to arrive or visiting a phone shop for activation.
While eSIM technology is gaining traction, not all devices are equipped with them. Most Google Pixel and Apple iPhone models released since 2018, along with Samsung's flagship phones launched after 2020, include eSIM functionality. However, you should check your device's specifications before assuming eSIM compatibility.
The UK eSIM market is still evolving, and the benefits of switching may not be worth it yet. Only a handful of UK mobile providers offer eSIM support: the major four networks (EE, O2, Three, and Vodafone) and some MVNOs such as Lebara & Spusu
While short European trips might not need an eSIM due to favourable EU roaming charges, they can be an excellent option for international travellers venturing beyond Europe. If you travel overseas frequently, an eSIM eliminates the need to purchase a local SIM card upon arrival, saving you the time and effort of finding a phone shop and the potential risk of losing your original SIM card.
How to find and open your phone's SIM card slot
You need to find and open your phone's SIM card slot to switch SIM cards. The slot is usually located in one of three places:
- On the exterior of the phone, on the side.
- Under the back cover of the phone.
- Under the battery of the phone.
If the slot is on the phone's exterior, you can use the SIM extractor tool (usually supplied with your new card) to push open the card tray. If the slot is under the back cover or battery, you will need to remove the back cover or battery to access the slot.
Once you have found and opened the SIM card slot, you can remove the old SIM card and insert the new one.
How to change the size of your SIM card
Most modern SIM cards come with an adaptor that lets you choose whatever size you need. The chip part fits neatly inside the plastic frame and becomes either a nano, micro or standard size, depending on your need. You can easily buy a replacement online if you have lost the adaptor.
Can you convert a standard SIM to a nano SIM?
It is possible to convert a standard SIM to a nano-SIM, but it is not recommended. The process of cutting down a standard SIM to nano size is risky, and you could damage the SIM card. The best way to get a nano-SIM is to contact your network provider, which should be able to send you a replacement SIM card.
Which SIM card does my phone need?
The size of the SIM card that your phone needs will depend on the model and manufacturer of your phone. Most smartphones today use nano SIM cards, while older models may use standard or micro SIM cards.
If you are unsure what size SIM card your phone needs, you can consult your phone's user manual or look up the specifications for your phone online. You can also contact your phone's manufacturer or network provider for assistance.
How to change your SIM card
Changing your SIM card is a quick and easy process, but there are a few things you need to know to do it like a pro.
First, you need to locate the SIM card slot on your phone. This is usually located on the side or back of your phone, and a small door or flap may cover it.
Once you've located the SIM card slot, use a SIM ejector tool or a paper clip to open the tray. Carefully remove the old SIM card from the tray, and then place the new SIM card in the tray.
The new SIM card should have a 45-degree notch in one corner. This notch aligns with the tray, so you'll know which way to insert the SIM card.
Once the new SIM card is inserted, close the tray and place the cover back on your phone. That's it! You've successfully changed your SIM card.
Can I keep my number when switching to SIM only?
Switching networks and keeping your number (or taking a new one) is such an easy process. To simplify the process, you can follow our guide: How do I keep my number when switching to SIM only?
Ready to buy your new SIM? Our SIM Only search compares the whole market for SIM Only Deals, so you don't have to!
