What's the difference between the SIM card in my phone and the SIM card in my tablet?


    The one in the tablet I'm paying only half price for that line, since I guess it is data-only.  But my question is, can I use a regular phone SIM card in the tablet?  Are they completely interchangable?  Would the one in my tablet work in my phone??  What about wearables (i.e. Galaxy Watch) that have LTE connectivity?  Do they use an external SIM or do they have an embedded SIM?  Can I use my phone SIM or tablet SIM in a wearable?  Is there a document somewhere that explains all the differerences between phone, tablet, and wearable SIMs??

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      • smplyunprdctble

        From a purely technical standpoint, there's probably no "real difference" between the SIM that is in your phone and the SIM that is in your tablet.  The SIM just tells the device how to connect to the network.


        From a monetary perspective (network-side provisioning), they're completely different.


        For a phone, T-Mobile requires you to have phone services, so the provisioning is for Talk, Text, Data.


        For a tablet, T-Mobile requires this to not have phone services, so you get provisioned for Data, and some tablets will allow you to text.


        The above two are (in every instance I know of, but may not be 100%) a physical SIM card you buy and insert in to your device.  You cannot use a SIM that is provisioned for a tablet in a phone or vice-versa.  But, hypothetically, if you went to T-Mobile and purchased two SIM cards, it shouldn't matter which you put in a tablet and which you put in a phone, it's just which gets provisioned for which.


        Wearables generally have an internal SIM (maybe a "soft-SIM"?), which is provisioned differently.  Some may have a SIM you can put in.  Not particularly sure how they work.


        Once a SIM card has been provisioned, it cannot be re-provisioned (again, not sure how the internal SIM of a wearable works with this).  So, you can't take a SIM your cousin had on a tablet and canceled the line and use it on a new tablet line of yours.


        T-Mobile recommends getting a new SIM every upgrade because the SIM contains information on how to connect to the network.  This is not required, but may impact your connection if the SIM is very old.  T-Mobile will replace defective SIMs for free, but if you want a new SIM and your previous wasn't defective, it will cost.  Sometimes you can sweet talk a replacement SIM for one that is pretty old (it's practically considered "defective" at that point).

        2 of 2 people found this helpful
        • magentatechie

          Great questions!  The SIM that goes in any of those devices is going to be the same however, the SIM number on the card is going to be associated with a specific type of line- either voice, mobile internet, or wearable.  ("Voice" doesn't mean only voice, but voice/data)


          Once the SIM has an association, it can be switched out between like devices.  (ex: If it were activated on a tablet line, the SIM can only be placed in a tablet)


          For wearables, the majority of them nowadays operate on an embedded SIM.  But there are some out there that do utilize a specific sized SIM card, though the card will still have to be activated with a wearable line of service.


          I hope I didn't make it more confusing!

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          • barcodeable

            I have to add some information regarding that “some tablets will allow you to text”. That statement is true, but the ability of your tablet being able to text depends also on your plan. I have noticed many of the Prepaid Tablet Plans and Prepaid Simple Choice Mobile Internet Lines are not capable of texting nor does T-Mobile provide international data, music freedom, or Data Stash with these plans. So please be aware that just because you buy a tablet plan doesn't necessarily mean  you will have the ability to text with that plan, no matter what fancy tablet you purchased.


            I also noticed T-Mobile is very, very vague when they describe what the Prepaid plan features include on some of their ads. When you start doing research, and once you put the puzzle together you will come to the realization of what you really signed up for. Just be aware that not all Tablets Plans and Mobile Internet Plans advertised by T-Mobile are the same. The price may look the same and they may have similar names to describe what they are (which may confuse most people) but look at each line and compare it to each other.... the Prepaid Plan lacks many features that you may want in a mobile internet/tablet line.