Apple's iPhone 5s may not have been a huge leap forward for Apple but it still represented a handset with tech that has made it stand the test of time. From the 64-bit processor to the fingerprint Touch ID sensor, this is still a powerful enough iPhone, even now.
But you probably already know that, and want to find out what SIM card size is correct for your beloved old iPhone 5S so that you can snap up one of our recommended SIM only deals. There's nothing old-fashioned about this though, as its the latest nano SIM that you require.
What is a nano SIM card?
The SIM is a card of many sizes and has changed over the years in a slimming sort of way. Going from the full-sized standard SIM, it's shrunk to mini SIM, then micro SIM and now is in the Nano SIM format for many phones.
Your chosen phone will have a certain size for you, in the case of the iPhone 5s that's nano.
How do I get a nano SIM card?
To get yours you can simply call up your network and they'll send one out free of charge. Alternatively you can pop into a shop and grab one there.
That means you can pick your network without the SIM being an issue, as they'll have the nano size to suit your iPhone 5S. Check out our guide to the best SIM only deals here to find the ideal one for you.
How do I keep my old number?
The freedom you have to pick your phone and SIM is matched by the ability to move about without the worry of losing your number. Yup, no need for the faff of telling everyone your new number.
The key is the PAC code. You can get this by calling up your current network provider. Then, when you get your new network SIM, presuming you want to change network, give them the PAC and they'll port across your number. A quick restart of the phone and you'll be up and running. While this can take up to 24 hours it's really that simple.
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Luke is a freelance writer and editor with over two decades of experience covering tech, science and health. Among many others he writes across Future titles covering health tech, software and apps, VPNs, TV, audio, smart home, antivirus, broadband, smartphones, cars and plenty more. He also likes to climb mountains, swim outside and contort his body into silly positions while breathing as calmly as possible.