June Wan/

This week, Apple announced its new iPhone 15, which, like last year's iPhone, forgoes the traditional physical SIM card for an eSIM. If you are upgrading from an iPhone that's at least two years old, it is likely that you will have to make to switch to the new data format.

Also: iPhone 15 eSIM: How to transfer your phone number to Apple's new iPhone

The transition will vary depending on your carrier, whether it supports eSIM or not (most of them do), and what practices they have in place to facilitate the activation. Most carriers will link your phone number to the device when you order your iPhone, making the setup process as straightforward and simple as possible. Others, maybe not.

Here's how the three major US phone carriers -- Verizon, AT&T, and T-Mobile -- are supporting eSIM activation. 

Verizon

Verizon

Verizon has an eSIM system in place that allows you to activate a phone in just a few steps. The process is especially easy if you purchase the phone from Verizon, of course. 

"If you purchased your iPhone from Verizon, or are a current Verizon customer, simply turn your phone on, follow the iPhone's setup steps, and you are good to go," Verizon tells . 

If you are switching to Verizon, you'll first need to connect to Wi-Fi to start the activation process. Then, download the "My Verizon App" from the app store or visit the Verizon website to activate the eSIM. Utilizing the same app, you can switch from other carriers or upgrade your account without needing a physical SIM card.

You can find step-by-step directions on the Verizon website. 

AT&T

AT&T

With AT&T, setting up your eSIM is similar. 

"AT&T makes it easy for customers to activate an eSIM if they're moving off an old phone or switching carriers. They can simply head to a store, visit ATT.com, or use the myAT&T app to set up and activate a new phone in minutes," AT&T tells . 

Also: Every iPhone 15 model compared: iPhone 15 vs. Plus vs. Pro vs. Pro Max

When switching from another carrier to AT&T and you're buying a new device, turn it on and follow the prompts to download your eSIM phone number. If you have an existing AT&T number and have a new iPhone, you can simply follow the setup prompts on the device.

You can find step-by-step directions on the AT&T website. 

T-Mobile

T-Mobile

T-Mobile is currently running a Network Pass program, which allows you to take advantage of the carrier's unlimited data via eSIM for three months at no charge. 

Also: Best Apple deals: the iPhone 15, MacBooks, AirPods, and more

To participate in this trial, the only requirement is to have an unlocked eSIM-compatible phone, like the iPhone 15. This is a great way to get a feel for how eSIM works and whether or not it's a good fit for your lifestyle.

If you plan on purchasing the new iPhone, like the other carriers, you can activate your T-Mobile eSIM by connecting to Wi-Fi and following the setup process on-screen. You may be asked to enter your T-Mobile account information or phone number to receive your eSIM data.

You can find step-by-step directions on the T-Mobile website. 

Apple

Unlock the best new features in iPhone 15, iOS 17, and Apple Watch with these tipsiOS 17: The most impactful new iPhone features are also the ones you'll notice the leastNew iPhone 15 models compared: iPhone 15 vs. Plus vs. Pro vs. Pro MaxOne subtle (but important) reason to buy the iPhone 15 Pro instead of the iPhone 14 Pro

• Unlock the best new features in iPhone 15, iOS 17, and Apple Watch with these tips
• iOS 17: The most impactful new iPhone features are also the ones you'll notice the least
• New iPhone 15 models compared: iPhone 15 vs. Plus vs. Pro vs. Pro Max
• One subtle (but important) reason to buy the iPhone 15 Pro instead of the iPhone 14 Pro