How does an eSIM work?

An eSIM (embedded SIM) is a digitised version of a standard SIM card that is built into eSIM compatible devices. This means that if you activate your plan with an eSIM, you don’t need to wait for a physical SIM to be delivered to start making calls or texting.

 

Embedded chips

eSIMs are stored within an on-device chip - an embedded Universal Integrated Circuit Card (eUICC). Measuring 6mm x 5mm, it’s much smaller than even a nano SIM card. In spite of its small size, it can store multiple user profiles and swap between them. This means that you can switch between SIM cards quickly and easily, without needing to physically handle multiple plastic SIM cards.

 

Digital activation

Traditional SIMs require physical handling. With eSIM, activation happens over the internet. You simply need to scan a QR code or activate it in the amaysim app and your plan downloads directly to the chip.

 

Carrier provisioning

When you activate an eSIM, amaysim prepares a unique profile containing your account details and authentication keys. This is encrypted so that only your specific device can open it. This process is called Remote SIM Provisioning.

 

Download & activate

When you scan a QR code or tap ‘Download eSIM’ in the amaysim app:

  1. Your phone receives a unique token and server address
  2. It contacts our amaysim servers over Wi-Fi
  3. The server verifies your token and prepares your encrypted profile
  4. Your phone downloads and installs this profile
  5. Your phone connects to the amaysim network

This entire process takes no longer than a few minutes. You’ll need to make sure that you have a stable Wi-Fi connection.

Want to get started? Learn how you can activate your amaysim eSIM here.

 

Why do we need SIMs at all?

When you make a call or use mobile data, your network provider needs to authenticate you. A SIM card handles this by storing a unique identifier for your account and cryptographic keys that prove you’re a legitimate user. 

eSIMs do exactly the same job. They authenticate you, store your plan details and instruct your phone how to connect. The only difference is how it’s packaged - digitally instead of in a plastic chip.

 

Can I store multiple eSIMs?

Yes. eSIM-compatible devices can generally store up to eight eSIM profiles. That being said, most devices can only have one or two of these profiles active at a single point in time. 

To use this capability, you can simply toggle between the different profiles in your phone settings. Your amaysim plan stays saved on your device even when it’s switched off.

 

Can I use an eSIM and a physical SIM together?

Most eSIM-capable phones still have a slot available for physical SIM cards, meaning you can have access to both at the same time. 

This is particularly useful for overseas travel. If you have your amaysim number stored on an eSIM, you’ll be able to either download an eSIM or pop in a physical SIM while travelling to be able to use your phone with a local provider. This setup is called Dual SIM Dual Standby (DSDS). Both lines stay connected so you can receive calls and texts on either, but only one can be actively used at a time. 

 

Interested in learning more? 

If you’d like to do more reading, check out our About eSIMs resource, which provides a concise overview of everything eSIM. Or to determine whether your device is eSIM compatible, read our eSIM device compatibility page.

Ready to get this show on the road? Check out our range of eSIM plans.