How Apple Watch’s innovative eSIM works

“Apple Watch Series 3 is Apple’s best smartwatch yet. It’s faster, packed full of new features in watchOS 4, and it boasts amazing new cellular connectivity (if you pay more for the LTE model),” Stev Smith writes fro Cult of Mac. “This is all made possible with a built-in antenna, a UMTS radio, and an eSIM. But how does it work?”

“An eSIM is a non-removable, virtual version of the traditional SIM card,” Smith writes. “It stores your international mobile subscriber identity (IMSI) and its associated authentication key. The big difference is its size; it’s one-hundredth of the size of a standard SIM card.”

“It’s an extra charge on your monthly contract,” Smith writes, “[but] for me, it’s worth that extra cost. Just the other today, before filming the video, I popped to a local shop without my iPhone and was still able to get a phone call from my friend who needed an answer on something straight away. The call was clear, he could hear me fine, and the connection was great.”

Read more in the full article here.

MacDailyNews Take: How long until the eSIM migrates into Apple’s iPhone?


  1. How long until the eSIM migrates into Apple’s iPhone?

    I hope very soon. With an eSIM, Apple could become essentially a “Super-MVNO”. Imagine having your iPhone where (optionally) the billing is handled through Apple. At any time, you could go into settings, see available carriers and select one as needed.

    You could be in a dead-zone for AT&T and need service, so you select Verizon for a day or month or whatever. More importantly, this would be awesome for traveling abroad, as you could switch carriers as you go, including international MVNOs.

    Let Apple be the one who handles our phone number, and the carriers be dumb carriers who compete solely on price and service without lock-in.

  2. I like the idea of the eSIM in pricinple, but the devil is in the details and I won’t want a phone with an eSIM unless I can switch carriers as seamlessley as if I had an actual SIM card slot.

    I often travel and if I’m staying in a place for more than a week I tend to buy a local SIM card. But I still slip in my home SIM from time to time if I need to.

    Also, I change plans a few times a year as my needs change and as the networks compete. I’d want to be able to do that with an eSIM.

    1. I’m imagining that’s how it would work… as long as Apple controls the number. The tech is there for it to work such that you wouldn’t have to go find a SIM and pop it in, and deal with whatever funky sign ups, activation and foreign number it gives you.

      Instead, at any time you could go to settings and it would show you what available carriers are in the area and what prices/plans they offer. Apple could even control this such that the plans are standardized Day, Month, Year, and by data/minute levels. You’d tap, tap, tap, and get billing through iTunes with no funky sign ups, activation, spamming, or foreign number to deal with.

      Some carriers could be MVNOs or International MVNOs and settings could be made automatic, meaning that you could do something like use AT&T locally, but use an International MVNO or a specific other carrier when abroad.

      All of this would greatly incentivize competition in pricing and service quality.

      Also, since this could be optional, any one carrier could be the number provider. So instead of Apple providing the Super-MVNO service, any local carrier could, thus providing competition for doing so through device subsidies, group plans, etc…

  3. Iirc Apple has wanted to use an eSim in iphone for several years but backed off because of carriers (“back orifices” per SJ) pressure. They would have sold service for carriers thru a store in iTunes. Such a pity it didn’t happen. Sounds great for consumers. Here’s hoping one day it will, even if it’s just as we migrate to the watch and leave the iPhone behind.

    1. Yes. Apple has previously proposed iPhones without SIMs but it has been resisted by carriers. I like to think that Apple is using eSIMS in Watch as a sneaky ‘proof of concept’ to demonstrate to carriers that it works in practice.

      My wife and I often travel between the UK and Germany and while I always keep my British SIM in my iPhone ( primarily to keep my same telephone number for incoming calls), I swap the SIM in my iPad for a German one so that I can use a lot of data without incurring massive roaming costs, we sometimes swap that SIM into my wife’s iPhone to make local calls when we need to. Public WiFi is relatively scarce in Germany, especially in the areas where we tend to go, so while WiFi in the hotel is fine while you’re there, while out and about, we rely on cellular data. I hope that any move towards eSIMs in iPhones also allows for temporary switching to a local supplier while travelling.

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