What's an eSIM and why is it important for the future of mobile?

What is an eSIM?

For most phones sold today and in the past several years, a SIM card is included or provided by your carrier to tell the phone how to connect to the network and what service it gets. These SIM cards look like small memory cards and usually slide into the side of your phone on a small tray. More recently, companies like Google and Apple have started to push an embedded SIM, or eSIM, as a better solution while still keeping a SIM card slot for compatibility.

This eSIM can be activated by a carrier to receive service without the need to get a specific SIM card from the carrier. Your eSIM could either be activated remotely by the carrier and in some cases, could even be done automatically.

Why would I want an eSIM?

One of the biggest reasons someone would want to have an eSIM is for easy access to new phone plans as needed. Some carriers provide phone service in an app and can activate services through your eSIM while you travel. This can allow you to keep your phone active on your standard line without risking massive roaming fees.

Some people may also want to have multiple numbers active on one phone. This can be great for someone that wants to be able to manage a business phone number and a personal number at the same time. It can also be a big help for someone that wants to make sure they have a solid connection in more places thanks to being able to access multiple networks. Google Fi can even use the eSIM in the Pixel 4 to improve coverage on its own service.

Having access to an eSIM in other devices such as smartwatches, tablets, or even notebook computers can make it easier to have data on those devices without having to worry about which carrier you will use. To add to that, removing a physical opening in the side of a phone can improve water resistance since current SIM trays rely on a gasket to keep water out. If it doesn't get seated properly or deteriorates, water can get in.

One of the main arguments against eSIMs is that people are afraid carriers will use the technology to lock phones out of activation on other carriers. While there is some plausibility to this, the end user is currently able to erase their eSIM on their own making it possible to activate on another carrier.