If you've found an old SIM card that you used years ago and then put aside, or if tidying up has turned up an old cell phone that you no longer use but that still has the SIM card inserted, surely you're wondering if that card is still active or has been disabled by the phone operator. If it is still active, in fact, you could use it as a second number or even dedicate it to two-factor authentication without risking becoming a victim of phone number theft or other scams.
How to find out if the SIM is still active? There are two very simple methods, but they do require some time on your hands. In case the SIM will not give any signs of life, you can also decide to cut it and throw it away: it will be impossible to recover the old number. Here's how to find out if your SIM is still active.
Find out if your SIM is still active by inserting it into your mobile phone
The first way to find out if the SIM you've found has not been deactivated is also the most logical: insert it into a smartphone and check if there is network coverage. Depending on the model of your smartphone to insert the SIM you'll have to open the shell or simply insert it into a slot on the side of the phone, then you can turn it on and enter the SIM security PIN. At this point, after a few seconds, if the SIM is still active it will connect to the phone network and the phone screen will display the name of the operator and the famous "notches" that indicate the quality of reception. Probably the SIM, even if it is still active, will have no credit and to use it you will have to recharge.
If the screen displays "No coverage", "SIM not active", "SIM disabled" or something similar, it means that the operator has disabled that card and the phone number associated with it. In this case the SIM card will be unusable and you can throw it away.
To be on the safe side, before doing so, make one last attempt by manually searching for phone networks on your smartphone. If it's an Android phone go to Settings > Network and Internet > Mobile Network > Advanced and turn off automatic network selection. At this point the scan will start and the available networks will be shown. If you have an iPhone, go to Settings & Mobile & Select Network and turn off automatic network selection. In both cases if there is the network of the operator of the SIM you are testing, try to connect to it: if the SIM is still active it will connect, otherwise not. If you don't see the network of the operator in question, then try again in another area, where that operator has coverage.
Find out if the SIM is still active with a phone call
The second method to find out if a SIM is still active is to call the number associated with the SIM. This method is useful, for example, if the SIM is in a different format than the one accepted by the smartphone and therefore you cannot insert it into the slot. The phone number associated with the SIM is printed both on the SIM itself and on the card that is provided by the operator, which contains it and which also contains the security PIN.
If calling the number it is unreachable or "The phone of the person called may be turned off" it means that the SIM is still active but has not been inserted into the smartphone (or is not working properly or there is no coverage). If, on the other hand, when you call that number you receive the response "Non-existent or no longer active number", then the card is now deactivated and should be thrown away.