Finding out your smart device is locked is usually a surprise, and befalls first-time SIM card users. Granted, this lock isn’t malicious. On the contrary, it’s there to protect you, as we’ll describe below. You can remove or change this protection too but only after you bypass the locking mechanism at least once. In other words, you’ll have to understand the whole thing initially, although we suggest you continue using it forever. After all, you have simplicity in your favor – the manufacturers have designed the feature with non-tech-savvy users in mind. Now, let’s get into how a SIM card lock works.
PIN SIM card lock: What is it?
Wondering what SIM PIN is? SIM card PIN is an acronym for Personal Identification Number, a 4 to 8 digit (numeric) code you must enter after you insert your SIM card, boot the device up, and try to access the home screen. It’s a primary SIM card locking mechanism, designed to prevent unauthorized use on the network for calling, texting, accessing mobile data, impersonation, etc. It effectively protects your SIM card from prying eyes, thieves, and hackers, SIM card readers, and even (sometimes) SIM card cloning.
Who sets a SIM PIN?
SIM PIN is configured at the factory where SIM cards are made and is usually identical for the entire batch or even the production line. The default PIN is often “0000”, “1111”, or “1234” for a 4-digit code, and continues the sequence for 5, 6, 7, and 8-digit PINs. Mobile network providers or individual carriers and MVNOs may choose to change the default PIN to one unique to their service to prevent easy access. Some carriers leave the default PIN intact but force their users to use a PUK code. In doing so, the user has to reset the default PIN and set a custom one. This prevents the thieves from checking the carrier-specific default code and breaking in.
Where do I find SIM PIN?
PIN for your SIM card is commonly printed on the full-size SIM card you punch a smaller-sized SIM card out of. It is hidden underneath a layer of silver foil you must scratch with any rigid object or tool, such as a dull knife or a key. Some carriers prefer to print the code on a piece of paper inside the package, leave it on the website, inside your user account Dashboard, or e-mail it to you.
How do I lock or unlock my SIM card?
Unlocking the SIM card PIN is easy – punch in the code, tap to confirm, and, if it’s correct, you’re in. This doesn’t apply to other types of SIM card locking. For those, you’ll find our comprehensive guide on unlocking a SIM card useful. On the contrary, if you disabled the lock on your SIM card before reading about things someone can do with it, the guide on locking a SIM card again will prove valuable.
What can I do without SIM PIN?
You can’t do much if you don’t know the PIN to your SIM. Because of the system SIM card lock works based on, you have 3 attempts to guess it before the carrier blocks it temporarily. To lift the block you must reset the PIN by entering a PUK code. In case you enter the PUK code incorrectly 10 times, the situation described in lock type #5 happens.
Other types of SIM card lock
We’ve covered the main way your SIM card lock works. Now, let’s dive into 5 more ways your SIM can be locked:
1. Carrier lock
Carrier-locking represents the procedure carriers use so that the devices they sell only work with their SIM cards or those from their MVNOs/sub-brands. Many know this process as Mobile Network Code (MNC) locking. They do it to prevent customers from switching sides and using a SIM card from a local competitor down the road. The SIM card can still technically use any network, proven by the fact you can still use roaming. Therefore, this practice is reversible and we laid out ways to combat it in the unlocking guide above.
2. Region lock
Mobile country code (MCC) locking represents an artificial lockout the carrier or device manufacturer applies to the device which affects SIM card functionality. Samsung is notorious for this practice; customers can only use their devices with a SIM card and an IP address from the region they purchased the device in. However, they’re easing up on this, and frequently mandate only the very first activation fulfills the conditions.
3. MSIN lock
Carriers impose this type of locking once again, but this time, they bind a device to an MSIN (Mobile Subscriber Identification Number). This means that users can only use the device with a single, unique SIM card. If unlocking is unsuccessful, customers usually get a phone number without a SIM card.
4. Remote lock
Remote lock refers to the temporary lockout of your SIM card issued by your carrier. The reason for it can be one of many, including:
- Your contract expired
- You didn’t top up your SIM card in time
- There is an outstanding balance on your account
- You lost your SIM card and are trying to find it
- You suspect your SIM card is hacked and requested a lock
5. Permanent lock
Entered PIN 3 times consecutively or PUK 10 times in a row? Did someone steal your device with a SIM card inside? Your activities broke your carrier’s Terms of Service? In all of those cases, your SIM card is blocked permanently. There’s no way to revert the change – you must buy a new one.