Phone Plans

What is an ESIM Mobile Plan?

Kyle Reyes
March 29, 2023

What is an eSIM Mobile Plan?

Embedded SIM cards connect to mobile plans the same way that physical SIM cards do. They are very similar in how they function within the device, and each one is essential for storing account-specific information that keeps your phone up and running. This section will discuss how SIM cards work, eSIM mobile plans, and the pros and cons of eSIM cards. 

Information Your SIM Card Stores

Your SIM card has a lot of specific data on it. Here’s some of the most important information stored on your SIM card:

  • Authentication Key: A string of numbers on your SIM (unique to you) that authenticates it on the network in which it is currently running 
  • Advice of Charge: An estimation of the mobile services cost for your phone
  • Local Area Identity: Identifying code that combines with your phone number and mobile country code
  • Mobile Country Code: This well-named piece of information shows the country from which you are calling
  • Service Provider Name: Put simply, it’s the name of the company from which you get your service
  • Service Dialing Number: Numbers you can dial to get information related to your mobile account
  • Unblocking Code: This is the code you need to open your phone if you put in the wrong PIN one too many times
  • Short Message Service Center: The process that delivers your text message
  • Voice-Added Services: Additional services you’ve purchased for your phone
  • Integrated Circuit Card ID: A unique number for your SIm that helps identify it. No two SIM cards have the same number. If that ever happens, it would lead to a lot of confusion. A lot.

This varies from phone to phone, but your IMEI number might also sit snugly in your SIM card. SIM cards generally store anywhere from 8 KB to 256 KB. The information they store is small compared to a lot of the other data we use, but it is very important. 

Accessing Your SIM Card’s Storage

There are a few different ways to access your SIM card’s storage if you ever need to. You can buy a SIM card reader, a device that allows you to output the data from the card onto a computer, or you can go into your settings to find it within the phone. 

On an iPhone, you can go into your settings and poke around until you see the info on your SIM card. On an android, you can go through a similar process to find the information in your phone’s settings. 

What Happens When You Take Out Your SIM Card?

Not much! Your phone turns from a smartphone to a smart device, but all the data is still there. You lose connection to your mobile data, but your phone won’t crash, factory reset, or anything scary like that. You’ll still have all your contacts, pictures, and data. While your phone will lose access to your number, it should sync back up when you put your SIM card back into your phone. 

Pros and Cons of eSIM Mobile Plans

Embedded SIM cards are growing in popularity, but physical SIM cards will likely remain in circulation for long. There are not too many differences between eSIMs and physical SIMS, and eSIM cards offer a lot of advantages over SIM cards, but have a different set of disadvantages as well. Let’s talk about the pros and cons of eSIMs. 


  • Easier to switch networks. Phones with eSIM cards are designed to switch instantly from one carrier to another, an advantage over physical SIMs, where you need to order a new SIM card from the new carrier and switch it out with the old one. 
  • No chance of accidental damage. SIM cards are teeny tiny, and there is always a chance for a mishap whenever you have to eject your SIM card. 
  • Store multiple networks on the same eSIM card. Many eSIMs can store multiple virtual SIM cards, letting you switch easily between networks if you run though areas with unreliable networks or travel to different countries. 
  • Dual-SIM devices often use eSIM cards. Dual-SIM devices are growing in popularity, letting you easily store multiple numbers on the same device and switch between them. 
  • Saves space. Last but not least, eSIMs take up less space than physical SIM cards, opening up the possibility for new phone models to be sleeker and more powerful. 


  • More difficult to swap devices. With a physical SIM card, switching devices is as easy as moving the SIM from one to the next. It has all your information stored on it, so all you have to do is transfer your contacts, pop in the SIM, and you are good to go. Swapping devices with eSIM cards is more involved and challenging. 
Switching out physical SIM cards is pretty easy, but an eSIM is always in your phone, ready to go! With an eSIM mobile plan there’s no need to keep those pesky SIM card removal tools. 

When to Use an eSIM Mobile Plan

Right now, the main draw for eSIM mobile plans are when you want two numbers on one device. If you only need one number, an eSIM mobile plan and a physical SIM mobile plan will get you the same results. There are a number of reasons why having multiple numbers on the same device is worthwhile, and there are a lot of phones that accommodate that goal. Let’s look at some of the times it makes sense to have two numbers on the same device. 

Two Numbers on One Device

Anyone with access to multiple numbers or plans could use an eSIM mobile plan. When you have multiple SIM cards on the same phone, you can switch between them at will. With a phone like this, you have an additional setting, normally in your drop-down menu, that lets you switch what the active SIM card is on your phone. While only one SIM card is active at a time in your user interface, you will receive text and call notifications from each number whenever it is relevant. 

This means that even if you are on the phone with someone that’s on your personal line you can still get a call from the other line. It will come through as a normal call and you can put your current call on hold or let it ring and keep talking to whoever is on line one. One important note — the data you use is tied to the SIM card that is active in the background. That means you need to be conscious of the SIM card that’s active if one of your plans does not have unlimited data. Other than that, the switch between SIM cards should be easy! 

Business Phones

There is nothing new about a phone just for business, but with an eSIM mobile plan you can keep your business number on your personal device. Since it is a separate number and separate account, you have more freedom to customize the notification settings than you would be working with only one number. You can, for instance, set your work number to be on do not disturb during non-work hours or when you are on vacation. This lets you keep the work-life separation without having a second device. 

This is also a great way to combine accounts if you travel internationally.  

International SIM Cards

A lot of people travel internationally with some regularity, and a dual SIM active phone lets you evade roaming charges and lower data speeds if you are in another country. While a lot of United States companies have international roaming agreements, those agreements can quickly add up in price if you spend a lot of time internationally. A lot of time means, generally, over a week each month. If you spend a lot of time in another country, an eSIM mobile plan lets you purchase a local plan, which gives you faster speeds and a much better deal on talk, text, and data. A dual-SIM device lets you keep both numbers on the same phone, but there’s also an option to purchase a cheap phone for international travel if you would rather keep it separate. 

Dual-SIM Active Phones 

Dual-SIM phones allow users to hold two separate accounts and numbers on one device. This is a classic way for people to separate their work from their non-work lives, especially if they, say, need to have their work phone online at all times and be able to answer it outside of work hours. A work phone with a separate ringtone allows those employees to know exactly when they are getting a work call. It also means that they can leave their work phone behind when they are truly off the clock. No Slack notifications or e-mails on vacation! 

That being said, carrying around two phones all the time is less than ideal. In terms of pocket space alone, two phones can be more than a bit inconvenient. The first dual-SIM phones gained popularity as mobile devices increased in complexity. Some people started to go crazy and created triple-SIM and quad-SIM phones, but they never caught on like dual-SIM phones have. You may have a dual-SIM compatible phone and not even know it! 

The transition from physical SIMs to eSIM cards marks an exciting time in technology. While phones are still optimized for physical SIM cards, soon eSIM mobile plans will overtake that.

How to Switch Accounts with eSIM Mobile Plans

Over the years you may have come in contact with a SIM card or two as you switched phones or providers, but they most likely took a backseat to what was more exciting at the time, being, well, the new phone or the new wireless carrier. SIM cards have changed a lot over the years, too! This section will cover the ins and outs of SIM cards and their transition into eSIM cards. 

The SIM card connects to your carrier’s networks so you are able to access data on the network. This is your calling, your texting, and your mobile internet. One of the big downsides of eSIMs is that they cannot physically switch from one phone to the next. To combat this problem, carriers all have their own ways to activate eSIM cards on new devices. The two most common are eSIM Carrier Activation and eSIM Quick Transfer. 

  • eSIM Carrier Activation — Your new carrier assigns an eSIM to your phone right when you activate it.
  • eSIM Quick Transfer — This is when you transfer from one phone to the next. If you are going from an iPhone to another iPhone, you can port over the SIM information without even contacting your carrier!  

You can activate your eSIM while you're setting up your iPhone if your carrier supports eSIM Carrier Activation or eSIM Quick Transfer. With eSIM Carrier Activation, your carrier assigns an eSIM to your iPhone when you purchase it. With eSIM Quick Transfer, you transfer the SIM from your previous iPhone to your new iPhone without contacting your carrier. With either method, to activate your eSIM during setup, turn on your iPhone and follow the instructions.

Transferring eSIM from Apple to Android devices, or vice versa, changes from carrier to carrier and, unfortunately, some carriers do not allow such a switch. 

What Happens to Phones Without Active eSIM Cards? 

If a phone doesn’t have an active eSIM card then it isn’t connected to a phone number and it can’t connect to any mobile network. It’s a lot like a tablet. The moment you activate your eSIM card again or a physical SIM card on the device, however, it should be back to full functionality. As long as it is a valid eSIM card to a valid account, any phone can return to being a fully-functioning device. 

Replacing Your eSIM Card

If something is wrong with your eSIM card there is, unfortunately, not much you can do. This is pretty uncommon, and would likely only happen if your phone gets pretty banged up. It is the same as if any other part of the internal hardware got damaged. If that’s the case it is time to go to the shop or, perhaps, get an upgrade! 

eSIM mobile plans are a new and exciting technology that will continue to grow in popularity as time goes on. 

Key Takeaways

Right about now we’d wager you feel pretty good about your knowledge regarding eSIM mobile plans. Just in case, we wanted to add in a few key takeaways to refresh your memory and ensure you leave this article with all its most important points in your mind. 

  • Most new phones have a physical SIM slot and eSIM ready in the phone, opening up your options for multiple accounts on the same phone. 
  • Carriers offer eSIM mobile plans and physical SIM cards, so you can choose which one works best for you. 
  • Overall, eSIM mobile plans are better compared to physical SIMs, but the benefits, at this moment, are still pretty small.
  • Businessmen and travelers often use dual-SIM phones to keep a work line and personal line on the same device.
  • Switching accounts with an eSIM mobile plan is relatively easy except in fringe cases, like if your carrier does not allow eSIM transfer from an Apple to Android device. 

Frequently Asked Questions

What are the disadvantages of eSIM?

It is harder to move from one device to another compared to SIM cards, and there are still some devices that don’t have eSIM compatibility. If your device does not — no sweat! SIM cards are completely valid ways to use your account. 

What is the difference between eSIM and SIM card?

An eSIM is a digital version of the physical SIM card that we all know and love. They both serve the same function, which is to identify your phone with the network, and are programmed remotely to be unique to your account. 

Why would I want eSIM?

While it is harder to switch devices with an eSIM card, it is much easier to switch carriers! There are well-run processes in switching from one carrier to the next if you have an eSIM card. The process should be painless and almost instantaneous. 

Should I convert my phone to eSIM?

At this point it is not that big of a deal, as long as you don’t have any SIM-related problems. SIM cards have been the norm for many years, and transferring carriers with physical SIM cards takes longer but is also a well-oiled process that should cause you no trouble. 

Can I use both eSIM and physical SIM? 

Yes! You can set up your phone to house two separate accounts, making use of the eSIM card and the physical SIM card. This is a common way for businessmen and travelers to condense the number of devices they carry along with them from place to place.

Kyle Reyes
Kyles Reyes is a journalist from Pittsburgh, PA that specializes in the wireless industry, phone plan comparisons & advice.
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