How to Activate an AT&T Phone: New Lines, Upgrades & Number Transfers

Activating a new AT&T phone is different from transferring your photos, contacts, apps, or other information. Whether you are activating a new line, upgrading an existing phone, or bringing a number from another carrier, the important step is making sure AT&T has activated the correct device and SIM or eSIM on the wireless line.

This guide covers standard AT&T Wireless activation. If the phone is on an AT&T Business account, use the more detailed AT&T Business Device Activation Guide.

Before You Activate an Upgrade

If you are replacing an existing phone, transfer your important information before activating the new device whenever possible. Activating the new phone can move cellular service away from the old phone.

• Transfer contacts, photos, messages, apps, and other important data.
• Make sure you know your Apple or Google account password.
• Move or prepare any authenticator apps used for two-factor authentication.
• Keep the old phone until the new phone is completely working.

How to Activate an AT&T Phone

1. Turn on the new phone and connect it to Wi-Fi if possible.
2. If the phone uses a physical SIM, make sure the correct AT&T SIM is installed. If it uses eSIM, follow the setup instructions provided on the phone or with your AT&T order.
3. Go to the official AT&T wireless activation page: att.com/activations/activatewireless.
4. Enter the wireless number and billing or shipping ZIP Code requested by AT&T.
5. Follow the activation and eSIM or SIM instructions shown for your device.
6. Restart the phone after activation if prompted or if service does not appear immediately.
7. Test a phone call, text message, and cellular data connection.

If you have a brand-new line with a new phone number, AT&T says the device may already be activated. Try making a call first. If service is not working, use the activation page above.

Transferring Your Number From Another Carrier

If you are bringing a phone number to AT&T, do not cancel service with your old carrier first. Your existing number generally needs to remain active until the transfer is completed.

Make sure AT&T has the correct information from your old carrier, including your account number and transfer PIN or passcode when required. Incorrect information can delay the transfer.

You can check the status of a transfer using AT&T’s Number Transfer Status page.

During a number transfer, there may be a short period when service behaves differently between the old and new phones. AT&T says mixed service can sometimes occur for several hours, and SMS/MMS messaging may take additional time to fully update. Depending on the previous carrier and type of transfer, the complete transfer process can range from a few minutes to several business days.

What About eSIM?

An eSIM is simply the digital version of a physical SIM. The exact setup process can vary by phone and by how the device was ordered. Follow the prompts shown on your phone and any instructions supplied with your AT&T order.

Do not assume that copying an eSIM or transferring information from your old phone means the AT&T line itself has been activated. After setup, always test calling, texting, and cellular data.

Content Transfer and Activation Are Different

Moving your photos, contacts, applications, messages, and settings does not by itself activate AT&T wireless service. Likewise, cellular activation does not guarantee that all of your personal information has transferred.

For an upgrade, the safest sequence is:

1. Transfer important information from the old phone.
2. Activate the new AT&T phone.
3. Complete any SIM or eSIM setup.
4. Test calling, texting, and cellular data.
5. Verify your apps, photos, contacts, and authentication tools.
6. Only then erase, reset, trade in, or ship the old phone.

Before You Erase or Trade In Your Old Phone

Do not erase the old phone just because the new phone turns on. Confirm that everything important is working first.

• Place and receive a call.
• Send and receive a text message.
• Turn off Wi-Fi and make sure cellular data works.
• Check your contacts, photos, messages, and important apps.
• Confirm any authentication apps or business login tools are working.
• Turn off Find My or other activation-lock features before a trade-in when required.

Having Trouble Activating?

If activation is not completing, first confirm that you are using the correct wireless number, device, SIM or eSIM, and account ZIP Code. Restart the phone after AT&T confirms activation and test it again.

For AT&T Wireless support, call 800-331-0500 or dial 611 from an AT&T phone.

Using an AT&T Business account?
Business activations can involve company ordering, ports, device enrollment, MDM, watches, tablets, hotspots, and other business-specific requirements. See the complete AT&T Business Activation Guide on WirelessConsultant.net.