Small isn’t always beautiful when it comes to SIM cards: with three different SIM sizes kicking around, it’s quite possible that the SIM from your current phone won’t fit your next one. If you’ve ever wondered how to use a nano SIM in a micro SIM slot, we’ve got the answers. Here’s how to use a nano SIM in any phone.
SIM card sizes explained
There are three kinds of SIM around: standard, micro and nano. Standard SIMs were the original and tend to appear in much older phones, such as the Galaxy S2 and HTC Desire HD.
The next size down, micro SIM, was developed to help make smartphones slimmer: when you’re trying to cram so much technology into a single case, every millimeter counts. Micro SIM slots appear in the Galaxy S3 and S4, HTC One X, Sony Xperia S, T and X and so on.
The next and final size is the smallest, the nano SIM. You’ll find nano SIM slots in the iPhone 5 onwards and on Android devices released within the last few years.
We say there are three sizes, but there’s actually a fourth and fifth option: a multi SIM, whose credit card-sized molding can be snapped out to make a standard, micro or nano SIM card; and a combi SIM, which can be snapped out as a standard SIM or micro SIM. You’ll often see multi and/or combi SIM cards when you’re looking at pre-pay phones or SIM-only contracts.
An important warning about using a nano SIM in a micro or standard SIM slot
You can put a tiny SIM in a larger SIM slot by using an adapter. There are huge differences between adapters, however, and a shoddy one can cause all kinds of problems. A loose-fitting SIM can get stuck inside the phone, and your increasingly angry efforts to get it out again can do serious damage to the phone’s delicate innards.
Unless you’re really good with fiddly technical things, getting a stuck SIM out is a job for your friendly neighborhood phone repairer.
What to look for in a nano or micro SIM adapter
In a word, quality. If the adapter requires tape or sticky plastic to hold the SIM in place, it isn’t going to be a perfect fit, and that means there’s a very good chance that once you put the SIM in, you’ll have a hell of a time getting it back out again. That means the really cheap SIM adapters can be a false economy (see above).
If you go Googling you’ll see lots of people saying nice things about Sadapter SIM adapters, which currently cost $13 for a three-pack on Amazon. These adapters are precision cut to the exact dimensions specified by international SIM standards, and are made of plastic that won’t deform unless you chuck it in a hot oven.
While it’s a bit fiddly to get the SIM in there (it’s a tight fit) you can be pretty sure that once it’s in it your phone, isn’t going to go anywhere. Other adapters are available, of course, but make sure you spend some time checking out the user comments – particularly from people who have the same phone as you.
How to use a nano SIM in any phone
The mechanics of using a nano SIM in a non-nano phone are simple enough. First choose the appropriate adapter – in this case the nano to micro one – pop in your SIM card and then pop the SIM/adapter combo in the card slot.
There’s another issue to think about though, and that’s the network lock. If the phone you’re putting the SIM into isn’t one you’ve bought as an unlocked phone, it may have a network lock. In plain English, that means a Verizon-bought phone will only work with a Verizon SIM, an O2 phone will only work with an O2 SIM and so on. If your phone is locked, simply popping in the SIM from another network won’t work.
We’ve got good news and bad news on that front. The good news is that it’s easy to unlock your phone; the bad is that it tends to cost money, because networks don’t really want you to switch to their rivals. The specifics differ from network to network, so you'll want to check with your provider for conditions.
If your phone is locked to a particular network, you normally need to fill out an online form and wait up to 10 working days for the unlock request to be processed.
Have you used a nano SIM in a micro SIM or standard SIM slot? Was the process painless or painful? Let us know in the comments.