What is an eSIM Card?

The term “eSIM” is becoming more and more common in the wireless industry. You may be familiar with SIM cards, but what is an eSIM card? The quick answer is that an eSIM card doesn’t technically exist. A SIM, short for Subscriber Identity Module, is a unique identifier inside every cell phone that helps wireless service providers to know the user’s assigned phone number and account information. Sort of like a thumbprint for your phone number. Up until recently, pretty much all cell phones had removable SIMs because they came on little plastic cards, hence “SIM card.” As with all technology, SIMs have evolved over time. In order to minimize the space occupied by physical SIM cards, a digitally embedded version, eSIM, was born.

Definition of eSIM

An eSIM, also known as an embedded SIM, is a completely virtual programmable card that does what physical SIM cards do: securely connect you with your network and provide access to your service so you can use your plan.

eSIM cards can easily be installed onto your phone via your phone carrier’s website or mobile app, and they’re essentially what makes your phone usable. Most of today’s cell phones still rely on physical SIM cards, but many in the industry believe eSIM to be the future and it’s only a matter of time before it’s more widely adopted. Some phones, like all iPhone 14 and 15 models, are eSIM-only and don’t even have physical SIM card slots, while other models, like the iPhone XR and iPhone SE, are compatible with both.

How does eSIM work?

Like we said above, eSIM works much like a physical SIM card. However, instead of having carrier data pre-stored on the card, your chosen phone carrier can send you their data over the Internet (using a QR code) or through a mobile app. Then, if you want to try different carriers or add a new number, that information can be downloaded onto the eSIM in a different slot (or reprogrammed into your eSIM entirely) instead of requiring you to swap out a completely different physical SIM card.

titled esim benefits: secure, dual sim, more room for battery/memory, greener

What are the benefits of eSIM?

eSIM is secure

Many experts recommend eSIM as a safer alternative to physical SIM cards. Another SIM card can’t be forcibly inserted into your phone, and switching numbers from one phone to another can be done virtually. We said earlier that the answer to “What is an eSIM card?” is that it’s technically not a card at all. Removable SIM cards are sometimes stolen by scammers who place them in other phones to gain access to someone’s messages, social media, or even financial records, while an eSIM cannot be stolen without stealing the entire phone.*

eSIM allows for multiple phone numbers on one phone

Several phone models allow dual SIM, which means two active wireless accounts on one phone. This enables you to have a work line and a personal line, or makes purchasing a local phone plan when traveling internationally easier since you don’t have to remove the SIM for your US phone plan. This also gives you the ability to purchase an international eSIM ahead of time, so you don’t have to wait to get a physical SIM card & plan when you arrive. You can have local calling & data as soon as you get off the plane. Dual SIM can work with either two active eSIMs or a nano SIM card and an eSIM, depending on which phone model you have.

eSIM is harder to lose

Like we mentioned before, you can’t steal an eSIM without stealing the whole phone. This means you can’t lose an eSIM without losing the whole phone either. When traveling internationally with eSIM, you don’t have to remove a physical SIM card to switch to a local plan. No physical card to remove means no physical SIM card to accidentally misplace while you’re out & about.  

eSIM eliminates the need for SIM trays

Getting rid of physical SIM cards, and thus SIM card trays, allows for thinner phones, bigger batteries or more memory. Embedded SIMs could also be used to make slimmer laptops or tablets, or even allow connected devices like fitness trackers and wearable technology to have 5G connectivity. 

eSIM also has an environmental benefit

Greater eSIM adoption means fewer physical SIM cards being created and shipped, as well as fewer SIM cards being thrown away. An eSIM is a green SIM.

gradient blue circle with a phone in the center that has a QR code to scan and titled esim vs physical sim

eSIM vs Physical SIM: Which is better?

This would usually be one of those subjective questions where it’s up to you what you’d consider “better.” However, yes, eSIM is a marked improvement over physical SIM cards for a few different reasons. 

An eSIM is a digital version of a SIM card and can do pretty much everything a physical SIM card does: it securely connects you to your carrier, allowing you access to your wireless service. The benefits we listed previously are what really set eSIM apart from a physical SIM card. The enhanced security of an eSIM, the dual SIM capabilities, the environmental benefits that come with no plastic or shipping materials, and the ability to activate almost instantly makes eSIM the obvious choice when both are available. 

In the interest of transparency, one benefit a physical SIM card has over an eSIM would be the ability to use it in an older phone if necessary. If your phone becomes damaged and you need to use an old backup phone temporarily, one that isn’t eSIM-compatible, you can just move your SIM card to that old phone.

How do you activate an eSIM?

Activating an eSIM is done online. Instead of visiting a retail store to purchase a SIM card or waiting for one to be shipped to you, an eSIM can be activated in minutes. All it takes is a few taps on your phone or a quick scan of a QR code to get started.

three people with white shirts on their phone smiling with the title getting started with esim on Ultra Mobile

How do I get started with eSIM on Ultra Mobile?

If you have a compatible, unlocked phone, joining Ultra Mobile via eSIM is pretty simple. When you go to purchase a plan at UltraMobile.com, just select eSIM delivery at checkout. Then, make sure your phone is connected to Wi-Fi, login to the email you used at checkout, and follow these steps to activate your new eSIM:

How to activate eSIM with iPhone

  • Go to Settings
  • Select Mobile Data
  • Select Add eSIM
  • Select Use QR Code
  • Scan your QR Code

How to activate eSIM with Android

  • Go to Settings
  • Select Network & Internet
  • Select “+” next to SIMS
  • Select Download A SIM Instead option
  • Select Next
  • Scan your QR code
  • Select Done

What phones are eSIM-compatible?

Since eSIM is still a relatively new technology, not all phones are eSIM compatible just yet. Currently, only certain Apple iPhones (including iPhone XS and newer, through the iPhone 15, which is eSIM only), some Samsung phones, Google Pixel devices and other Android phones are eSIM compatible. Use the link below to see if your phone is eSIM compatible before purchasing a plan and activating an eSIM at UltraMobile.com. You can also head to your nearest Ultra Mobile retailer to activate via eSIM if that’s your preference.