What type and size SIM card do you need?

SIM cards aren’t one size fits all, in fact, they come in three different sizes – not including eSIMs – and the size you’ll need will depend on what handset you have.

As such, we can’t definitively tell you which SIM card size or type you’ll need, but read on below for an explanation of the three sizes, ideas of which you’re likely to need, and help in finding out for sure, along with a brief overview of eSIMs.

What types of SIM card are there?

There are three main types of SIM card: standard, micro and nano. A standard SIM is a full-size SIM card and therefore the largest of the three. A micro SIM card is smaller, and a nano SIM is smaller still.

However, you also get multi SIMs, combi SIMs and trio SIMs. These contain two or – more often – all three SIM card sizes in one. If you need a standard SIM, you just put the whole thing in your phone, for micro or nano SIMs there are weakened areas that let you pop the smaller size out.

You may also see reference so eSIMs. These are SIM cards that are built into the phone, rather than being something that can be put in or taken out. Many phones now support these, but not many networks do, and they are almost always joined by a conventional SIM card slot, so aren't something you should need to worry about, but if a phone does come with one of these (and the network you're using makes use of it) then you won't need a physical SIM card at all.

At the time of writing, Three, Vodafone, EE, O2, Lyca Mobile, and Giffgaff support eSIMs, and in most cases you get one by first ordering a physical SIM card and then requesting a swap to an eSIM. So you’ll still typically initially need a nano SIM card.

How do I know which SIM card type I need?

That’s the one question we can’t definitively answer for you, as it will depend on what phone you have, but the short answer is that you’ll probably need a nano SIM.

The longer answer is that if you have a phone that launched from around 2014 onwards it’s likely to use a nano SIM, as the majority of modern smartphones do. If it launched between roughly 2010-2014 then a micro SIM is more likely to be needed, and if your phone launched before 2010 then it may well need a standard SIM. However, that’s just a rough guide.

To be sure, your best bet is to search on the internet for which SIM card size your specific make and model of phone takes. If you still have the documentation which came with it this might also say.

You can also always compare your current SIM card to the various different sizes, this is especially easy if you’ve already received a multi, combi or trio SIM.

If you’re more interested in eSIMs, then you’ll need a phone launched from roughly 2019 or 2020, and even then, only select – mostly high-end – handsets include them. But again, in almost all cases your phone will also have a slot for a removable SIM card.

Do I need to find out my SIM card type before ordering a SIM Only deal?

Generally not, as the vast majority of networks will send you a multi, combi or trio SIM, so you can work it out once your SIM card has arrived. Check out our network pages for more information on each specific network and what kind of SIM cards they provide.

Even if you want an eSIM, in most cases you’ll need to order a removable SIM card first, so simply place your order and worry about SIM card sizes and types once it arrives.

What if I need to change SIM card size?

If you need to change SIM card size at a later date – say, for example, if you get a new phone which takes a different size, then you have a couple of options.

You can either request a new card from your network, or use an adaptor with your existing card. Sometimes these are provided with multi/combi/trio SIMs anyway, but if not they can usually be picked up for no more than a few pounds, and let you make a small SIM card bigger.

If you need to go down in size and aren’t using a multi, combi or trio SIM (which allows you to just pop out a smaller size) then your best bet is to request a new card from your network.

There are SIM card cutting tools, but there’s always a risk you’ll cut it the wrong size and still have to request a new one.

For switching to an eSIM, there’s no adaptor, so in this case you’ll have to request the swap with your network.