AT&T is considered one of the largest four carriers in the United States, along with Verizon, T-Mobile, and Sprint (the latter two have merged last year). In fact, AT&T is the largest telecommunications company in the world and the second-largest provider of mobile services. The company offers unlimited data plans, internet service, AT&T TV, a large selection of the latest mobile devices from the best brands, quality service, reliable nationwide coverage, responsive customer service, frequent special deals for both new and existing customers, and much more.
AT&T has a huge number of subscribers and you may be one of them. If that is the case, you may be wondering how to activate an AT&T SIM card. Luckily, you have come to the right place as in this article you will find out all you need to know about AT&T SIM card activation.
What Should I Consider Before Starting the AT&T SIM Card Activation Process?
Before you decide to activate your AT&T SIM card and whether or not you wish to become an AT&T subscriber in the first place, here are some things you should consider.
Choose a Device or Check AT&T Compatibility
AT&T provides a large number of mobile devices, including basic flip phones and the latest and most advanced smartphones from the best brands. You can check out the carrier’s selection and purchase one at att.com/buy/phones. In case you already have a phone that works perfectly for you and you wish to stick with it, AT&T allows you to bring your own device. The phone you bring must be unlocked and compatible with AT&T services and network. You can read more about AT&T’s BYOP program at att.com/wireless/byod and check if your phone is compatible at m.att.com/shopmobile/wireless/byop/checkIMEI.html.
In case you also need information 10 Best AT&T Refurbished Phones
Compare AT&T Plans
AT&T offers three unlimited plans, a 4 GB plan, international plans, as well as special discounted plans for military and veterans, nurses and physicians, first responders, and teachers. Their most popular plans include:
- AT&T Unlimited Elite. The plan comes with unlimited talk, text, data, 100 GB of premium data (after 100 GB the data speeds may slow down in times of congestion), 5G access, unlimited talk, text, data in Mexico and Canada, unlimited texting from the U.S. to over 120 countries, advanced mobile security, HD streaming, 30 GB of hotspot data per lime per month, HBO Max, and Stadia Pro. It costs $50 a month per line if you get 4 lines.
- AT&T Unlimited Extra. The plan comes with unlimited talk, text, data, 50 GB of premium data, 5G access, unlimited talk, text, data in Mexico and Canada, unlimited texting from the U.S. to over 120 countries, advanced mobile security, SD streaming, 15 GB of hotspot data per lime per month, and Stadia Pro. It costs $40 a month per line if you get 4 lines.
- AT&T Unlimited Starter. The plan comes with unlimited talk, text, data, 5G access, unlimited talk, text, data in Mexico and Canada, unlimited texting from the U.S. to over 120 countries, advanced mobile security, SD streaming, and Stadia Pro. It costs $35 a month per line if you get 4 lines.
Check AT&T Coverage
AT&T has the second-best coverage in America. It connects over 99% of all Americans. Their network is available throughout the country, however, as their towers are not equally distributed, you must make sure that the carrier has good coverage and a strong signal in your area. To do so, go to att.com/maps/wireless-coverage.html and either search the provided map or enter your address, state, or ZIP code.
Check AT&T Customer Service
AT&T offers reliable and responsive customer service. They can answer all of your most frequent questions at att.com/support. They are also available by phone at 800.331.0500 or 611 from a mobile device for wireless support and 800.288.2020 for internet and TV support. You can also contact them and find more options at att.com/support/contact-us.
What Do I Need Before Activating My AT&T SIM Card?
Before you start your AT&T SIM card activation process, make sure to prepare all the things that you will need or be required to provide.
- Your AT&T SIM Card
- Your AT&T mobile device (either original or a compatible device from another carrier)
- Your name, address, account PIN, and other personal and account details, which you will be required to provide
- Your phone’s IMEI and SIM card number
What to Do Before the SIM Card Activation
- Step 1: Insert SIM Card Into AT&T Compatible Device: Once you have your AT&T SIM card and an AT&T or BYOP compatible device, the first thing to do is to insert the SIM card into the phone. It’s best to use a new SIM card, otherwise, you can also use an old compatible one.
- Step 2: Check the Status of the SIM: Before you attempt to activate your SIM card, it’s best to check whether or not the card is already activated. If you have purchased it from a retailer, they may have done the activation for you. You can check the card’s status (whether or not it is activated) by placing a call. If it goes through, your SIM card is activated, otherwise, you can proceed with the activation process.
- Step 3: Steps to Activate AT&T SIM Card: After inserting the SIM card into a compatible device and confirming that the SIM card is not yet activated, you can activate it by following one of the methods provided in the following chapters.
How to Activate AT&T SIM Card
There are several AT&T SIM card activation methods. You can activate your SIM card over the phone, on their official website, or at a retail store. Decide which method is most convenient for you and then simply follow the steps provided below.

Activate an AT&T SIM card at a store
In case you decide to purchase your AT&T SIM card at a store, chances are that the professional at the counter will activate the SIM card for you. If he or she doesn’t do so, you can ask them to and they will be able to complete the activation process in a matter of minutes. This way, you will avoid doing the activation steps yourself. You can find the nearest AT&T store or retailer at att.com/stores.
Activate an AT&T SIM card online
You can activate your AT&T SIM card online. To do so, follow the steps provided below.
- Step 1: Go to att.com/help/business/get-started.
- Step 2: Select what you wish to activate – your device or SIM card.
- Step 3: Enter the required information.
- Step 4: Follow the provided prompts to complete your activation.
Activate an AT&T SIM card by phone
In case you are unable to do the activation process online, you can visit an AT&T store or contact AT&T’s customer service at att.com/support/smallbusiness/contact-us. There, you will find the right number to call. AT&T customer service is available 24/7. If you’re in the US, dial 1-800-331-0500. If you are in another country, dial 1-314-925-6925. The system or representative will guide you through the activation process.
How to Activate AT&T SIM Card Manually
To activate your AT&T SIM card manually on their website and the phone, follow the instructions below.
- Step 1: Find your phone’s IMEI number. It is written on the phone’s packaging. However, if you don’t have the packaging, you can get the number by dialing *#06# on your phone. Once you find it, write it down, as you will need it.
- Step 2: Find your SIM card number. Your SIM card or ICCID number is printed on the SIM card next to ‘ICCID’, ‘CSN’, or ‘EID’.
- Step 3: Optional: Transfer a phone number from another provider. If you wish to transfer your number from T-Mobile or Verizon, for example, you can do so on AT&T’s website at att.com/checkmyorder/activations.
- Step 4: If you haven’t done so already, insert the SIM card into the phone. To do so, turn your device off, carefully insert the SIM card into the slot and turn the phone back on.
- Step 5: Make a test call. If you can place a call, your SIM card is activated and you can finish the activation process. You can then set up voicemail and review the ‘Device Support’ option at https://www.att.com/businesssupport/ to learn how to use and troubleshoot your device. Otherwise, continue with the next step.
- Step 6: Go to att.com/help/business/sim-get-started. Here you can activate your SIM card.
- Step 7: Enter the SIM (ICCID) and IMEI numbers and press continue.
- Step 8: Follow the provided on-screen instructions to activate the card.
Activating an AT&T SIM Card Online
AT&T makes it really easy to activate a SIM card or a device online. All you have to do is the following:
- Step 1: Go to att.com/help/business/get-started and select the thing you wish to activate. You can activate your phone, SIM card, eSIM, AT&T Wireless Internet, tablet, accessory, or wearable. Press on the option you prefer.
- Step 2: Regardless of what kind of a device or card you chose to activate, you will be asked to locate your SIM (ICCID) and IMEI numbers.
- Step 3: Regardless of what kind of a device or card you chose to activate, you will have the option to transfer your contacts, photos, and videos.
- Step 4: Provide the required information and press ‘Continue’.
- Step 5: Follow the on-screen instructions to complete the activation process.
Activating an AT&T Prepaid SIM Card
You can activate your AT&T prepaid SIM and device online. To do so, follow the instructions below.
- Step 1: Go to att.com/prepaid/activations/#/activate.html.
- Step 2: Enter your 20-digit SIM or ICCID number in the first box. On the right side of the screen, you will see the exact instructions on where to find the SIM or ICCID number.
- Step 3: Enter your phone’s 15-digit IMEI number in the second box. On the right side of the screen, you will see the exact instructions on where to find your phone’s IMEI number.
- Step 4: Enter your 5-digit service ZIP code in the third box. Make sure to enter the ZIP code of the area where you are planning to use the device the most.
- Step 5: In the fourth box, retype the provided ‘Passphrase’ to prove that you are not a robot.
- Step 6: After providing all the required information, press ‘Continue’ – located in the bottom right corner. Enter your email.
- Step 7: Choose a plan that will best fit your needs. If you select Auto Pay, it will bill you monthly. Agree to Terms and Conditions by checking the box and press ‘Continue’.
- Step 8: Your SIM card is not active and it has a number. Now, all you have to do is add credit and you can use your AT&T prepaid service.
Activate AT&T eSIM on a Dual SIM Setup
eSIM cards are electronic versions of the traditional physical SIM cards. To activate an AT&T eSIM on a dual SIM setup, go to att.com/help/business/get-started, select ‘eSIM’ – the third option from the left, and follow the instructions provided below.
- Step 1: Take your smartphone and go to ‘Settings’
- Step 2: Select the ‘Cellular’ option.
- Step 3: Press the ‘Add Cellular Plan’ option. The Camera app will open automatically.
- Step 4: If you received a QR activation code from AT&T (it can be either printed on a card or in email), point your camera at the QR code on your eSIM card. Your phone will scan the QR code and you will see a message saying ‘Installing cellular plan’. This will activate the AT&T eSIM on your mobile device.
How to Activate an Old AT&T SIM Card
In case you have a used or old SIM card that you never had the chance to activate, you can do so by following the simple steps below.
- Step 1: Notice the SIM card number written on the bottom of the card. Write it down as you will need it.
- Step 2: Go to your computer and open the browser. Open AT&T’s activation page at att.com/help/business/get-started.
- Step 3: Select the device or card you wish to activate and follow the on-screen prompts. Enter the required information.
- Step 4: Wait for the system to notify you that the activation is complete.
How to Activate a Replacement AT&T SIM Card if My SIM Card Got Lost, Stolen, or Damaged?
Activating a replacement SIM card is no different than activating any other AT&T card.
If your AT&T service is already active and you simply need to activate a replacement SIM card as it got lost, stolen, or damaged, you will probably simply need to order a new AT&T SIM card and insert it into your phone. After turning the device on, try placing a call. If it rings, the SIM card is already activated. If not, go to att.com/help/business/get-started and press ‘SIM card only’. Follow the on-screen instructions.
In case you have both a new SIM card and a new phone, you will probably need to activate it. To do so, go to att.com/help/business/get-started and choose the device or card you wish to activate. Once you do so, follow the provided instructions, and your replacement SIM card will be activated in no time.
What to Do if I am Unable to Activate my AT&T SIM Card?
In the unlikely event that none of the AT&T SIM card activation methods provided above works for you, you have three options.
- Try again after some time: Restart your phone and then wait for a couple of hours before you try the process again. AT&T may experience some temporary issues, especially in peak hours. Therefore, give it some time and retry the activation process on your own.
- Contact AT&T’s customer service: In case you have already tried to activate your SIM card more than once and if you were unsuccessful each time, your best bet is to contact AT&T’s customer support service. They will be able to identify the issue, fix it, and let you know how to proceed.
- Visit the nearest AT&T store or retailer: In case even AT&T’s customer support service is unable to help you, they will probably suggest you visit an AT&T retailer. The best thing would be to revisit the retailer where you purchased the SIM card. If there is something wrong with the SIM card, they will be able to identify it and replace the card if necessary (for example, if the SIM card chip is damaged), which will surely resolve the issue.
How to Add Credit During AT&T SIM Card Activation?
In case you have a prepaid SIM card and if you have completed the activation process described in the ‘Activating an AT&T Prepaid SIM Card’ section, your SIM card is active and had a number as soon as you complete the last step. However, the plan isn’t ‘live’ yet, as you haven’t added any credit. You can add credit right after you complete the last activation step or you can do it later.
If you wish to add credit to your AT&T Prepaid SIM card online, simply follow the instructions below.
- Step 1: Go to paygonline.com/websc/loginPage.html.
- Step 2: Sign in to your AT&T Prepaid account by providing your 10-digit wireless number and online password. Press ‘Sign in’.
- Step 3: Press ‘Make a Payment’.
- Step 4: Choose the payment method.
- Option 1: You can select ‘Pay’ under ‘Credit Card, Debit Card or Checking Account’, enter the amount you wish to add, press ‘Continue’, and follow the instructions to complete the payment.
- Option 2: Another way to pay is by using an AT&T prepaid card. In this case, scroll to ‘AT&T Prepaid Refill card’ and enter the prepaid PIN located on the back of the card. Press ‘Continue’ and wait for the payment confirmation’.
- Option3: Select ‘Auto Pay’. This way your plan will automatically renew itself each month. Choosing this option will save you $5 to $10 a month.
If you wish to add credit to your AT&T Prepaid SIM card by phone, follow the instructions below.
- Step 1: Call 611 directly from your AT&T prepaid phone or call 800.901.9878 from another phone.
- Step 2: At the main menu, say ‘Payment’.
- Step 3: Select ‘Make a payment’.
- Step 4: Choose to pay with your credit card, debit card, or refill card.
- Step 5: Follow the provided prompts to complete the payment.
You can also add credit to your AT&T Prepaid account by using the star services. To do so, simply dial *888* + PIN number + # (for example: *888*1234567899874#). You will receive a confirmation that your refill payment was applied.
What Benefits Do I Get if I Activate My AT&T SIM Card?
Activating an AT&T SIM card and thus becoming an AT&T customer, comes with a long list of benefits, for both the new users and the existing ones.
Benefits For New Users:
- Great AT&T products (phones, accessories, gift cards, etc.)
- Same-day delivery and expert setup on new devices
- Great unlimited plans
- Specials discounted plans for military and veterans, nurses and physicians, first responders, and teachers
- Plans packed with features (for example, international calls and HBO Max subscription)
- The second-best coverage in the U.S.
- Premier customer support
- VIP giveaways with chances to win trips, products, and VIP tickets to sporting events and premieres
- Spotify Premium access
- Friday Access – weekly chances to win gift cards, promotions, and much more
- Special deals for new users may include a cheaper device or a cheaper plan
Benefits For Existing Users:
- Great AT&T products (phones, accessories, gift cards, etc.)
- Same-day delivery and expert setup on new devices
- Great unlimited plans
- Specials discounted plans for military and veterans, nurses and physicians, first responders, and teachers
- Plans packed with features (for example, international calls and HBO Max subscription)
- The second-best coverage in the U.S.
- Premier customer support
- VIP giveaways with chances to win trips, products, and VIP tickets to sporting events and premieres
- Spotify Premium access
- Friday Access – weekly chances to win gift cards, promotions, and much more
- Special deals for existing users may include a cheaper device or a cheaper plan
FAQ
Can I Get a Free SIM Card From AT&T?
In case you wish to activate a new device and qualifying plan, you will receive an AT&T SIM card completely free of charge. The free SIM card can be for a new phone, tablet, or smartwatch. On the other hand, if you are planning to buy a Prepaid AT&T SIM card, you will have to pay $4.99.
Read one of our past articles Government Free Phone
Does the AT&T SIM Card Support CDMA or GSM?
Like T-Mobile, AT&T also uses GSM technology, therefore the carrier’s SIM cards are GSM-enabled.
Does AT&T Charge for SIM Card Activation?
In case you are starting a new line or service, you will have to pay a $30 activation fee. If you are switching your SIM card on an existing line to an older phone, you will not be required to pay the upgrade fee, however, if you wish to switch to a new phone, you will be required to pay the upgrade fee.
Can I Use My New AT&T SIM Card with Any Phone?
AT&T offers a BYOP (Bring Your Own Phone) option, therefore it allows customers to use their AT&T SIM cards with any unlocked and compatible phone. To check whether or not your phone is compatible with AT&T’s network and services, go to m.att.com/shopmobile/wireless/byop/checkIMEI.html.
How Long Does It Take to Activate an AT&T SIM Card?
The SIM card and device should be working after 20 minutes of activation. However, it can take up to 24 hours. You can check if the device and SIM card are activated by trying to place a call. If the SIM card is still not activated after this time, make sure to call AT&T’s customer service and ask them what the issue is.
Does AT&T Allow SIM Swapping?
Yes, AT&T allows swapping active SIM cards between devices. To do so, go to att.com/support/article/wireless/KM1001034 and follow the provided instructions.