For years, the main way your phone got service was through a physical SIM (subscriber identity module) card that connected your handset to your phone carrier. SIM cards make it easy to swap phones or carriers whether you’re getting a new device or traveling. Nowadays, however, most modern phones also support eSIMs. Rather than a physical card, eSIMs are embedded directly into the phone and the carrier information is programmed remotely via software.

Whether you choose a physical SIM or an eSIM depends on several different factors, so we’ve outlined a few commonly asked questions below. 

What do physical SIMs and eSIMs do?

A physical SIM card is essentially a tiny card with a chip that connects your phone to your wireless carrier. It contains identifying information like your account info and phone number. Without it, your phone won’t have a number or any way to connect to a carrier and you won’t be able to make or receive calls and text messages. 

Some phones allow you to remove the physical SIM card, which allows you to easily swap phones or carriers. This is useful if you want to use your existing number in another phone, or if you want to use your phone with another carrier. Just insert a different SIM card, and you can connect to a different cell network. For years, some phone supported having dual SIM cards. You might have your home number on one and your work number on the other.

An eSIM, however, is embedded directly into the phone’s circuitry and cannot be ejected or removed. Instead, all the carrier information is programmed remotely via an app. The biggest advantage of eSIMs is that it allows one phone to have multiple lines even from different carriers. This is especially useful when traveling, as you can add a global eSIM provider without having to purchase await in line for a physical SIM when you arrive at your destination. For more on eSIMs, you can check out our explainer here. You can also move your service from one phone to another without needing to dig out a SIM ejector tool, but you might need to call your wireless service provider for assistance.

Can I have both an eSIM and a physical SIM?

Yes, many phones allow you to have an eSIM and a physical SIM simultaneously, even from different carriers. You can use both simultaneously, or you can designate one as active while the other is on standby. Some people designate one number for work while the other is for personal use. 

How do I switch phones with a physical SIM or an eSIM?

To switch phones with a physical SIM, all you have to do is eject it from your existing phone and then insert it into a new one. This typically works regardless of the phone you are switching between, allowing you to move your service from an iPhone to Android phone at will.

With an eSIM, your carrier can either transfer the number over for you or you can do it yourself through your phone’s settings. Your carrier will often send detailed instructions on how to do so. Typically it’s easy to transfer your eSIM when moving to a phone of the same operating system, for instance moving from an iPhone 14 to an iPhone 16 where both are on iOS or from a Samsung Galaxy S21 to an S25 since both use Android. If you are switching between iOS and Android, you’ll likely to call your provider for assistance.

Converting an existing physical SIM card to an eSIM is fairly easy too, though it sometimes requires more steps. You can check out our guide on how to do so here, or you can refer to your carrier for more specific instructions. 

Do any phones require eSIM?

Yes, some phones are eSIM-only and therefore require eSIM. iPhone 14 models and newer are eSIM-only in the US, meaning they lack a physical SIM card slot. Most Android phones include both a physical SIM slot and support for eSIM.

Do all phones accept eSIM?

Most modern iOS and Android phones accept eSIM, such as the newer iPhones, the Pixel 6 and the Samsung Galaxy S21 and newer. Simpler phones, however, like HMD’s Barbie Phone and the minimalist Light Phone do not. For those phones, you’ll want a physical SIM card.