If you're considering switching to a new network to save money, looking to improve signal or if you're selling your phone and need to know the state of its carrier lock beforehand, here, we show you how to check to see if your phone is unlocked and how to unlock it if it isn't already.

There are a number of reasons why you might want an unlocked phone or tablet if it has cellular connectivity. Maybe you want to use a different SIM card when abroad for cheaper calls, texts or browsing, or want to simply switch mobile networks. Perhaps you've purchased a phone online and want to know if it's locked to a particular network, or want to make sure it's unlocked in order to sell it.

If your phone or tablet is locked, you will only be able to use a SIM card from the mobile network it's locked to. This can be very frustrating if you need to use a SIM from a different network, only to find that your phone (or tablet) won't let you.

If you purchased your phone SIM-free (and you've purchased it brand new, rather than second-hand), it's almost definitely going to be unlocked to allow you to decide which SIM you want to put in it. However, buying one on contract from a phone retailer or a network might mean that it's locked from the get-go.

Locked phones are much less common now than they used to be, and it's much easier to unlock them than it once was, so there's no need to worry if you do discover that your phone won't accept SIM cards from other networks out the gate. It might cost you a small fee, and sometimes you'll need to wait until your contract is up to unlock your phone, but these factors really hinge on the network your phone is locked to.

How to check whether your phone is unlocked

If you have the phone on your person – whether it's an iPhone, Android phone or something else – then the easiest thing to do to check whether your phone is unlocked is by trying different SIM cards from other networks/carriers in it.

Borrow a SIM card from a friend or family member that's from a different network to the one you've been using, and pop it into your phone to check whether you have any signal. If not, it's likely that your phone is indeed locked. You might also be greeted with a message asking for a SIM unlock code, which is also proof of a carrier-locked phone.

Is my iPhone locked

We'd also recommend restarting the phone before checking, as it sometimes takes a restart for the SIM card to be picked up by the device itself.

If you can't readily tell whether the newly inserted SIM card is working or not, try making a phone call. If the call doesn't connect, it's likely that your phone is locked.

If you don't have the phone yet because you're the one buying it, you'll have to ask and trust the seller to find out. Even if it does turn out to be locked, however, there's an easy fix in most cases, so it's unlikely to render your new phone useless.

Note: You may find apps claiming to be able to tell you if your phone is unlocked but we would avoid using this method, as they can't necessarily be trusted. Simply trying different SIM cards is your best option.

If you find that your phone is indeed locked, follow the links below to go to the unlock page for your network.

Alternatively, use a third-party unlocking app like DoctorSIM. We would recommend being careful to only use an unlocking service you trust. We have tested DoctorSIM and found it to be successful and fairly priced, but some will charge significantly more and not all services are legitimate, so reasearch is recommended before you part with any cash if you decide to go this route.

We have more information about how to do this in our article how to unlock a phone to use any SIM.