If you buy a phone that is locked to one carrier, putting a different carrier's SIM requires an unlock code, which is often expensive to obtain and confusing to enter. They have practically no function without an accompanying smartphone and are increasingly reliant on third-party apps to address functionality, such as connecting to multiple networks or using more than one phone number.īecause they are simple pieces of plastic, their benefit is largely subject to the will of the carrier. Likewise, if you travel internationally you can just buy a SIM card from a local carrier - as long as your phone isn't locked to a carrier. If you buy a new phone, you can simply insert your existing SIM and keep on using your existing service as long as the new phone isn't locked to a different carrier. They make connecting to networks and switching phones as easy as removing a small metal tray. SIM cards are the unseen magicians of today's smartphones.

Check out our how to remove the SIM card in an iPhone or iPad guide to get started. If your iPhone runs out of power and you desperately need to make a call or connect to the internet, you can just swap the SIM into another iPhone and use it with your minutes and data bucket.

Where is the sim card in an iphone