The classic question for those considering a SIM Only plan - answered.

SIMs might not seem like much, but those little microchips are the beating hearts of our phones and tablets. Without them calls, texts, and data use wouldn’t be possible.

And while they all work the same way and do the same job, SIMs also come in different sizes.



Standard SIM

The “normal” sized SIM. It’s the one you probably remember from your first ever mobile phone. They’re only used in older phones and devices now – like the iPhone 3GS and Samsung Galaxy S II.



Micro SIM

As the name suggests, the micro SIM is a smaller version of the standard SIM. It’s about half the size. And while it was first used with iPhone 4, most modern smartphones now use a micro SIM.  



Nano SIM

At around 40% smaller than a micro SIM, the nano SIM is the smallest of the lot. Apple’s made it the standard SIM for every phone from the iPhone 5 onwards. That includes iPhone 8, iPhone Xs, and iPhone 11 Pro. However, the iPhone XS and iPhone 11 also have eSIMs too.


What about eSIMs?

Heard about eSIMs but not sure what they are? Well, they connect you to a network like a physical SIM but, they’re a virtual, electronic version. Some of the phones which have eSIM are the iPhone Xs, iPhone 11, iPhone SE and the Galaxy S20 series. In time, it’s likely that most, if not all phones will have eSIMs. It would reduce the cost of producing the plastic SIMs plus it’s better for the environment too.



Why have SIMs changed in size?

It’s mainly down to advances in technology – a smaller SIM means you can have a thinner, lighter phone. You’d be surprised how the newly saved space can be used to cram in other impressive bits of hardware. 

Need a replacement SIM?

If your SIM is the wrong size, getting a replacement is easy.

Just give us a call or go into any Three store. If you’re heading into your local store, don’t forget to take valid photo ID with you.

Pay Monthly account holders can also get a replacement SIM by using our online request form.

What about a SIM adapter?

Need a bigger SIM? Instead of getting a completely new one, you’ve got the option to use a SIM adapter instead. This handy bit of kit lets you use a smaller SIM in a device that needs a larger one.

You can pick one up for free from any Three store or by giving us a call.

Want to know more? Check out this guide – How to use a SIM adapter.

Getting a SIM Only card from Three

You can use a Three SIM in any unlocked 3G, 4G, or 5G phone or tablet.

If you got your device from us, it’ll be unlocked as standard. But if it’s locked to another network, we can help you unlock it.

Happy with your phone or tablet? We’ve got loads of SIM Only plans available too – go check ‘em out.

And if you’re not quite ready to commit to a Pay Monthly plan, we’ve got you. Order your free Pay As You Go SIM today.