There were a lot of news stories out this past week covering the fact that Apple started selling variants of the iPhone 7 as "SIM Free." Most of the news sites are just simply reporting that these "SIM free" versions of the iPhone 7 and iPhone 7 Plus are now available, but they don't really explain the difference between unlocked and SIM free.
The Physical Difference
If you buy an iPhone, either through a carrier or even through Apple's Upgrade Program, the iPhone is still delivered to you with a SIM card already installed. This means you have to make a choice of carrier when you purchase the phone. Now, when you unbox that beautiful new iPhone 7 or iPhone 7 Plus it is ready to activate on the network of the carrier you chose at the time of purchase. So that it the physical difference between unlocked and SIM free. Unlocked comes with a SIM card installed (when buying the phone brand new) and SIM free phone come without a SIM card (you must supply your own SIM card and install it before the phone can fully function). Both a carrier unlocked phone and a SIM free phone can be used on other carriers as they are both not locked to a single carrier (at least from a network perspective). In other words, the carrier has not locked either the unlocked phone or the SIM free phone to their network so it is free to be used on another carrier's network. But just because you can take your unlocked or SIM free phone to another network doesn't mean it will actually work on another cell carrier's network.
The Band Differences
Beyond just the difference of the unlocked iPhone 7 having a SIM card and the SIM free iPhone 7 coming without any SIM card there are other differences as well. In the case of the iPhone 7 the other major difference between unlocked and SIM free is the supported LTE bands. I could literally write several thousand words trying to explain all the differences between the unlocked iPhone 7 and the SIM free, but I won't. Instead, I will just summarize it this way. The SIM free version of the iPhone sold by Apple are essentially the same iPhones as the ones you get when you get an iPhone 7 for the Sprint or the Verizon networks (they just come without a SIM card and are not pre-configured to work on a specific network). In other words, it is an iPhone that comes with a Qualcomm CDMA modem. CDMA is a cellular technology that is used by Verizon and Sprint, while AT&T and T-Mobile use GSM. So if you buy an iPhone 7 to specifically use on AT&T or T-Mobile it comes with an Intel modem that uses GSM technology.
So what does buying a SIM free iPhone 7 mean if you want to use it on AT&T, T-Mobile or over seas? An iPhone 7 bought specifically for AT&T or T-Mobile (which means is has the Intel modem and only supports GSM) will NOT work on other U.S. cell carrier networks. But a SIM free iPhone (which has the Qualcomm CDMA modem) will work on all the major U.S. cell carriers (AT&T, T-Mobile, Sprint and Verizon) because the Qualcomm modem (while primarily a CDMA modem) will also support GSM. From an international perspective you are probably ok with any iPhone 7 you purchase. Most foreign cell networks use GSM as their cellular technology so all variants of the iPhone 7 support this. But there are always outliers so check Apple's compatibility website for any countries you may visit before you decide.
It is important to note that the only way you can purchase a SIM free iPhone 7 in the U.S. is by purchasing it directly from Apple (either online or in one of their Apple Stores). Cell carriers and 3rd party re-sellers like Best Buy are not selling the SIM free variant of the iPhone 7. The SIM free iPhone 7 also does not come with any financing options like you can get with Apple's Upgrade Program or through carrier financing. So if you want a SIM free iPhone 7 then you are going to need to buy it directly from Apple and you will have to pay the full price up front.
So Who is a SIM Free iPhone For?
In summary, the SIM free iPhone 7 is mostly for people who plan to use their iPhone on more than one U.S. cell carrier network (because it works with them all) and for people who do a lot of foreign travel (because again, it gives them the most compatibility). But this is a very small percentage of the population. For most people, just getting an unlocked iPhone 7 through Apple's upgrade program or even an iPhone 7 directly from a U.S. cell carrier is going to serve them just fine. Hopefully this post helped you. It was driving me crazy reading all of the news articles about the SIM free iPhone 7 and having NONE of them explain what the difference between unlocked and SIM free really meant.