How to Activate a SIM Card or eSIM: A Step-by-Step Guide

Getting a new phone or switching to a new phone service is an exciting upgrade, which requires activating a new SIM card or transferring a SIM if possible. Whether it’s an eSIM or a physical SIM card, the steps vary slightly between carriers (and in some cases, between operating systems). It's important to follow the right steps for your particular situation.  

The SIM card is what lets you connect to a cellular or data network so you can use your phone away from Wi-Fi. So it’s crucial for enjoying your new phone or new service.

We put together this easy-to-follow guide that will help you activate almost any SIM card. You can use these links to jump directly to the section you need: 

• How to activate a physical SIM card
• How to transfer a physical SIM card to a new phone
• How to activate an eSIM
• How to transfer an eSIM to a new phone

How to activate a physical SIM card for Android or iPhone

Note: Beginning with the iPhone 14 in 2022, Apple has switched to eSIMs only in iPhones. If you have a 14 or later model, read about how to activate an eSIM on an iPhone or see below for general eSIM activation info.

1. Insert the SIM card in your phone

The first step is quite simple:  

• Turn off your phone or put it on Airplane Mode.  
• Locate the SIM card tray (usually a notched-out slot on the side). 
• Take out the SIM card tray by inserting a SIM card ejector tool into the small hole near the tray. 

• Insert your new SIM card into the tray (it’s cut out to match the shape of the card, so it’s impossible to put it in the wrong way). Some SIMs come packaged in plastic that lets you punch out the correct size of SIM card for your phone.
• Slide the tray back in then turn on the phone or turn off Airplane Mode.

2. Activate the SIM card with your carrier  

Most carriers require you to activate the SIM card before you can use it. After you insert the SIM card into your phone, you may see that it connects to a network but you’re not able to get any service (the signal bars have an X over them), or that it struggles to connect to a network. In that case, follow the specific steps outlined by your carrier to complete activation. Those prompts should be provided by the carrier with the shipment of the SIM card, or you can follow these instructions for the Big 3 networks:

How to activate an AT&T SIM card  

If you have a desktop computer or laptop, it’s recommended to follow these steps there, but if not, you can use your new phone over Wi-Fi to complete them. 

For a new AT&T customer: 

• After turning the phone back on, follow the on-screen setup prompts. 
• You can then either call 1-800-331-0500 to complete the process OR complete the process online by going to AT&T’s activations page:
  - Choose AT&T Wireless or AT&T Prepaid (if you have a prepaid SIM card) and follow the prompts to activate your device.  
• Restart your phone to configure the new settings. 

For an existing AT&T customer:  

• You can either call 1-800-331-0500 for customer assistance or activate your new phone online:
  - Log into your My AT&T Account’ page.  
  - Select the line you're looking to activate the SIM card on, then choose Manage Device & Features.  
  - Update the SIM card number (the ICCID) and follow the on-screen instructions to complete the activation.  
• Restart your phone to configure the new settings.  

How to activate a T-Mobile SIM card  

If you have a desktop computer or laptop, it’s recommended to follow these steps there, but if not, you can use your new phone over Wi-Fi to complete them.  

For a new T-Mobile customer:  

• After turning the phone back on, follow the on-screen setup prompts.  
• You can then either call 1-800-T-MOBILE to complete the process OR complete the process online by going to the T-Mobile account page:
  - Log into your T-Mobile account.
  - Select the line to activate the SIM card on (if you have multiple lines).
  - Follow the steps to verify your account.
  - Enter your ICCID number (found in your device settings) to confirm the change. 
• Restart your phone to configure the new settings.  

For an existing T-Mobile customer: 

• Turn off SIM Protection if it’s enabled. 
• After you insert the SIM card and turn your phone back on, the service should start working within a few minutes. If you’re having issues with signal or service, you can follow T-Mobile's troubleshooting steps.

How to activate a Verizon SIM card  

If you have a desktop computer or laptop, it’s recommended to follow these steps there, but if not, you can use your new phone over Wi-Fi to complete them. 

For a new Verizon customer: 

• After turning the phone back on, follow the on-screen setup prompts.  
• You can then either call 1-877-807-4646 to complete the process OR complete the process online by heading over to the Verizon My Account page:
  - Log into your Verizon account.  
  - Select the Activate or Switch Device page. 
  - Enter the required information, such as the ICCID number (located in your device settings), and IMEI (dial *#06# on your phone’s keypad).  
  - Follow the steps to complete the activation.  
• Restart your phone to configure the new settings.  

For an existing Verizon customer: 

• Log in to your My Account page on Verizon’s website.  
• Select the Activate or Switch Device page.  
• Complete the steps listed there to activate your new phone.  

3. Restart your phone  

Once you've completed your carrier activation steps, restart your phone by turning it off and back on. That lets the phone reset to the new configuration and connect to the network.  

4. Test out the connection  

Even if everything looks good and you see a network connection, you still want to test it out. Check that calls and texts go through, and that you have data access on your mobile browser without Wi-Fi. If not, contact your carrier for further troubleshooting steps. Some carriers may require you to change APN settings on your phone in order to connect to the network.  

How to transfer a physical SIM card to a new phone

With a physical SIM, you may be able to simply move the card from your old phone to the new one to continue service. Here's how:

• Make sure the new phone is unlocked (able to be used on any carrier) or is locked to the same carrier as your old phone.
• Make sure both phones use the same size of SIM (most phones now use nano SIMs).
• Back up data such as photos, contacts, apps, etc. They're not stored on the SIM and have to be moved over separately.
• Power off both phones.
• Take the SIM out of the old phone and put it in the new phone's SIM tray.
• Power on the new phone and see if it connects to the network. If not, restart the phone.
• Sync the phone with the backed-up data to move photos, apps, contacts, etc. to the new phone.

Note that some carriers may require you to get a new SIM card rather than simply moving your existing one to a new device. In that case, follow the steps to activate the new SIM when you receive it.

How to activate an eSIM for an iPhone or Android

1. Find your activation details  

After purchasing an eSIM, your carrier should provide you with activation details, which will most likely be a QR code or an activation code.  

2. Enter the activation details into your phone’s settings  

An eSIM activation is fairly consistent across all devices, with some minor differences based on where you scan the QR code or enter the activation code.  

Activate eSIM on an iPhone:  

• Go to Settings > tap Cellular. 
• Tap Add eSIM.  
• Choose Use QR Code or Enter Details Manually. 
• Scan the QR code or type in the details as provided by your carrier.  

Activate eSIM on an Android:  

• Go to Settings > tfap Networks & Internet.  
• Select Mobile Network > Add SIM.  
• Choose Download a SIM Instead. 
• Scan the QR code or enter the details manually as provided by your carrier. 

3. Follow the on-screen instructions 

Once you've entered activation details, follow the on-screen instructions to complete the process.  

4. Restart your phone  

It may not be explicitly asked, but it’s recommended that you also restart your phone (turn it off and back on) to configure the settings properly.  

5. Test out the connection  

Check that calls and texts go through, and that you have data access without Wi-Fi. If that’s not the case, contact your carrier for further troubleshooting steps.  

How to transfer an eSIM to a new phone

Make sure your carrier supports eSIM transfer, then choose the path the fits your situation:

iPhones:

• Sign in to your Apple Account on both devices, unlock them, and enable Wi-Fi and bluetooth.Follow the onscreen prompts to use Apple's eSIM Quick Transfer process.
• If Quick Transfer doesn't work, you can transfer the number after setup by going to Settings > Cellular > Add eSIM > Transfer from another phone.
• If you want to transfer an eSIM from an Android to an iPhone, go to Settings > Set Up Cellular > Transfer from Android and follow the prompts.

Apple has good step-by-step help guides on various eSIM activation and transfer configurations.

Androids:

• Turn on Wi-Fi and bluetooth for both phones. Go to Settings > Connections > SIM Manager and tap Add eSIM. Choose the option to transfer from another phone and follow the prompts.
• If that doesn't work, go to your carrier's website and look for a "SIM swap" or "bring your own device" option and follow instructions.
• If you want to transfer an eSIM from an iPhone to an Android, begin the setup process on the Android. You'll be prompted to scan a QR code on the Android with your iPhone, which will connect the devices and let you select what you want to transfer, including the eSIM. You can also start the process from your iPhone by going to Settings > General > Transfer > Transfer to Android.

Types of SIM cards  

There are two main types of SIM cards: eSIMs, which are embedded in the phone and not removable, and physical SIM cards that you can insert and remove.

How do I know if I have I have eSIM or SIM?

There's a good chance your phone has eSIM capability, and in fact it may be eSIM only. In the U.S., iPhone models 14 and later have eSIMs only and are dual SIM. Most later-model Androids also support eSIM and may pair it with a nano SIM in a dual SIM set-up.  

To find out what kind of SIM card you have, you can search online by model name, such as “type of SIM card in Moto G Stylus.” You can also search by model name and “dual SIM” to see if your phone supports more than one SIM.  

You can also simply remove your phone’s physical SIM and look at it. If it’s mostly chip with very little surrounding plastic, it’s a nano.  

Physical SIM vs. eSIM: Pros and cons  

In addition, cards differ based on whether they’re for a postpaid phone plan or a prepaid phone plan.  

A postpaid SIM card is used to activate a postpaid phone plan, which is a type of plan that bills you for service after the month ends. These are more commonly used by the Big 3 carriers (AT&T, T-Mobile, and Verizon) and lock you into a contract. These tend to be the most expensive plans, up to $100 a month for one line, but there are many affordable phone plan alternatives.

A prepaid SIM card, on the other hand, allows users to pay for mobile services in advance. That lets you access much more affordable prepaid phone plan options. It's also the most common type of SIM used by international providers for affordable coverage while you're travelling.

Postpaid vs. prepaid SIM Card: Pros and cons

FAQs about activating SIM cards