How to Use a Mobile Phone With Two SIM Cards
By Alexander Poirier
Mobile phones that use Global System for Mobile Communications (GSM) technology store the phone's user and carrier information on a Subscriber Identity Module (SIM) card. Some phones come with dual SIM slots, allowing users to install and use two SIM cards at once. Most cell phones, however, only have one SIM card slot, meaning that only one SIM card can be installed at a time. Nevertheless, if a single SIM cell phone user has two SIM cards from either the same or different carriers, it is possible for her to use them interchangeably.
Dual SIM Cell Phones
Locate the cell phone's dual SIM card slots. For many dual SIM cell phones, the SIM card slots are located in the battery compartment, behind the battery itself. See the supporting documentation that came with your phone for specifics.
Insert both SIM cards into the dual SIM card slots and reassemble the phone as necessary. The orientation of the SIM cards may vary from phone to phone, so see the documentation that came with your device for details.
Turn on the phone. Some dual SIM card phones have a button or interface option that allows you to switch between SIM cards, while others have a separate send button for each SIM card. Others allow you to activate or deactivate the SIM cards in the phone's "Settings" menu. See the documentation that came with your dual phone for specific details.
Enable the SIM card you wish to use to place and receive calls. When you wish to use the second SIM card, enable it and, if necessary, disable the first one.
Same Carrier SIM Cards
Locate the cell phone's single SIM card tray. For many cell phones, the SIM card is located in the battery compartment, behind the battery itself. Other cell phones, such as the iPhone, have the SIM card located in a tray that pops out of the edge of the device. See the supporting documents that came with your device for specifics.
Remove the SIM card from the SIM card tray and insert the second SIM card into the SIM card tray. Reassemble the phone as necessary.
Use the phone with the second SIM card installed. As long as the two SIM cards are on the same carrier (and have a data plan attached to them, if required) the phone will be functional, regardless of which SIM card is installed. Any time you want to use a different SIM card, switch the SIM card out in the SIM card tray.
Different Carrier SIM Cards
Contact your cell phone provider and request an unlock code or unlock service for your device. Some cell phone carriers will provide you with an unlock code after a specified period of account activity, while others require that you are no longer under contract with the carrier to receive an unlock code. Others will request that you send your phone into the cell phone carrier so that they may unlock the phone for you. Once the phone is unlocked, however, it can be used with any GSM carrier's SIM card.
Remove the SIM card from the unlocked device and insert the other carrier's SIM card into the SIM card tray.
Use the cell phone with the other carrier's SIM card installed as you would with the original SIM card. Whenever you switch the SIM card, the cell phone will be tied to the appropriate carrier, so switch the SIM card as needed.
Alexander Poirier began writing professionally in 2005. He worked as the editor-in-chief of the literary magazine "Calliope," garnering the magazine two APEX Awards for excellence in publication. Poirer graduated from the University of the Pacific with a Bachelor of Arts in English.