Let's say you spent your vacation abroad a couple of years ago. Being thrifty, you removed your U.S. SIM card from your unlocked iPhone 4 and inserted a SIM card from a carrier in the country you were visiting.
You did this because you knew that if you used your phone abroad and didn't have an international calling plan, you could run up some huge phone bills. By replacing your SIM card with a local card, you probably saved a substantial amount of money.
Now you're going back to that country, and you still have that SIM card — from your iPhone 4. Uh-oh. That won't fit in an iPhone 5, 5s or 6 or 6Plus. You need a smaller SIM for those, known as a nano SIM.
Have you lost your investment?
Not if you have a SIM card cutter. You can trim your old card, as the video above shows, and use it in your new iPhone, assuming it, too, is unlocked, which means you're not tethered to any carrier and can change carriers at will.
For instructions on how to get your phone unlocked — generally, you either purchased your phone outright or you have paid it off — see this post for the complex but not complicated instructions I followed. Or call your carrier.
Now you have a right-sized SIM card. Or you've purchased one from a seller when you arrived at your foreign destination. Or you bought one in advance from a company such as L.A.-based Cellular Abroad or another provider. (Google "international SIM card.") Remember when you are buying a plan that your bigger expense may not be telephone calls but data.
The video above also shows you how to replace that SIM in your iPhone 6 or 6 Plus. It is relatively easy, and it does afford you some protection from big bills upon your return home.
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