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

Visible SIM card next to Pixel 3a
Visible SIM card next to Pixel 3a (Image credit: Ara Wagoner / Android Central)

Best answer: An eSIM integrates the functions of a SIM card into a phone's hardware, making it easier and quicker to change phone service. Using an eSIM can also make it easier to manage multiple phone services on one device.

What is an eSIM?

For those asking, "What is an eSIM and why is it important?" Most phones sold today, and in the past several years, come with 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. However, companies like Google and Apple have recently started to push an embedded SIM, or eSIM, as a better solution while still keeping a SIM card slot for compatibility.

A carrier can activate this eSIM to receive service without getting 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. Many of the best cell phone plans support eSIM though you may need to contact the carrier to get your eSIM information.

Why would I want an eSIM?

One of the biggest reasons someone would want to have an eSIM is easy access to new phone plans. In addition, 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 who wants to manage a business phone number and a personal number simultaneously. It can also be a big help for someone who wants to make sure they have a solid connection in more places, thanks to accessing multiple networks. Google Fi can even use the eSIM with a standard SIM in the Pixel 4 or newer to improve its service coverage. Pixel 4a 5G and Pixel 5 even have access to 5G coverage with the dual SIM feature.

Galaxy S20+ 5G network with SIM cards

Source: Samuel Contreras / Android Central (Image credit: Source: Samuel Contreras / Android Central)

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 worrying about which carrier you will use. Also, 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 can now erase their eSIM on their own, making it possible to activate on another carrier.

Samuel Contreras

When Samuel is not writing about networking or 5G at Android Central, he spends most of his time researching computer components and obsessing over what CPU goes into the ultimate Windows 98 computer. It's the Pentium 3.