A SIM card — or subscriber identity/identification module — is a small memory card that contains unique information from your carrier's mobile network, and connects your phone to your carrier's mobile data in order to make calls, send messages, and access the Internet.

SIM cards are interchangeable and can be switched between compatible devices, allowing you to take advantage of multiple mobile data plans, especially when travelling abroad.

 

Choose a topic

What type of SIM card will my phone use?	➜
What SIM card will I need?	➜
eSIM	➜
Setting up eSIM on an iPhone	➜
Setting up eSIM on an Android	➜
The eSIM isn't working	➜
Dual SIM	➜

 

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What type of SIM card will my phone use?

 

All modern smartphones (since the iPhone 5) use a Nano-SIM. Some older devices use a Micro-SIM. And much older ones (like the original T-Mobile Sidekick or early flip phones) use a Mini-SIM. If you're still unsure, find out the exact device model you're looking to buy and consult the official website of the manufacturer to see if your SIM card will work.

 

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Which SIM card do I need?

100% chances are that you need a Nano-SIM. To make sure your SIM card/mobile plan is compatible with the phone you’re shopping for, contact your carrier. 

If you need to know which carrier(s) you can use with a particular device, knowing the model number of the phone will help. For example, if you’re a Verizon customer and want a refurbished iPhone 12, it can help to get the A2172 specifically for optimal service.

Phones bought on Back Market do not come with a SIM card. If you need a new SIM card, you'll need to contact your carrier.

Find your carrier:

AT&T	(800) 331-0500	Web	BYOD
Boost Mobile	(833) 502-6678	Web	BYOD
Cricket	(800) 274-2538	Web	BYOD
Google Fi	(844) TALK-2-FI	Web	BYOD
H2O Wireless	(800) 643-4926	Web	BYOD
Metro	(888) 8-METRO-8	Web	BYOD
Mint	(800) 683-7392	Web	BYOD
Spectrum	(877) 463-0677	Web	BYOD
Straight Talk	(877) 430-2355	Web	BYOD
T-Mobile	(800) 937-8997	Web	BYOD
US Cellular	(888) 944-9400	Web	BYOD
Verizon	(800) 922-0204	Web	BYOD
Xfinity	(800) XFINITY	Web	BYOD

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eSIM

Manufacturers began adding an embedded-SIM (eSIM) to their mobile devices in order to allow users to get service without a physical SIM card. Not all US carriers support eSIM, so be sure to check your carrier to see if they have any eSIM plans.

Setting up an eSIM is pretty easy, and your phone should walk you through the steps when first booting it up, but if you're having any trouble, here's a quick walkthrough.

iPhone

Before you try to connect, check if your carrier supports eSIM. Once confirmed, there are a few ways to set it up:

1. Scanning the QR code

   • Your carrier should have a QR code if they support eSIM

   • Find that QR code through your carrier account, then scan it with the camera app on your device

   • Click Cellular Plan Detected > Continue > Add Cellular Plan
     
     

2. Assigned Cellular Plan

   • For iOS 13 or newer, your carrier can assign the plan directly to you

   • Once assigned, you'll receive a notification that says 'Carrier Cellular Plan Ready to Be Installed' — open it to continue

     • You may be asked to transfer your cellular plan if switching to eSIM

   • If you receive the notification, follow the steps on the screen and select the desired phone number

   • Once complete, make a call to ensure the setup was successful

     • If the call doesn't work, contact your carrier directly
       
       

3. Enter the information manually

   • Go to Settings > Cellular/Mobile Data > Add Cellular Plan > Enter Details Manually

 

Android

While the Google Pixel 2 only supports eSIM for Google Fi, newer models, and some Samsung Galaxy devices support eSIM for other carriers. Before purchasing your device, make sure that your carrier supports eSIM.

1. Scanning the QR code

   • Depending on your carrier, you may also receive manual information instead of a QR code. If so, click the Enter information manually button and fill out those details

• Go to Settings > Network & Internet > Mobile Network > Add carrier

• Scan your carrier's QR code

• Click Start and wait for your phone to update

• Once done, click Complete

 

The eSIM isn't working

An eSIM is an embedded SIM card in the device, which means that it doesn’t have a physical sim card you can remove — it's a 'software SIM card'. The information stored in the eSIM can be edited so if you decide to change carriers or plans, there shouldn't be a problem.

If your eSIM isn't working or if your device says 'No Service':

• Make sure that your device is unlocked 

• If you just activated your eSIM, it can take up to 5 hours to convert a SIM card into an eSIM

• Restart the phone, especially if you just activated the eSIM

• Toggle Airplane Mode on and off

If nothing happens after troubleshooting, contact your carrier. They may need to set you up with a new eSIM.

If your eSIM is still showing "No Service," or your eSIM is still not working after you've gone through some basic troubleshooting using the above techniques, please reach out to Back Market Customer Care.

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Dual SIM

If you have a business and a personal number, travel out of the country often, or have a separate data and voice plan, a dual SIM device is a great option. To see if the device is enabled for dual SIM, check the technical specifications of the product listing.

Once you receive the device, you'll need to insert both SIM cards and follow the on-screen steps to activate each plan.

iPhone

The following iPhone models can use dual physical SIM cards:

iPhone 13 iPhone 13 Pro iPhone 13 Pro Max iPhone 12 iPhone 12 Pro iPhone 12 Pro Max

iPhone 11 iPhone 11 Pro iPhone 11 Pro Max iPhone XS Max iPhone XR

Learn more about dual SIM and iPhone.

 

Android

For Android, here are the most popular models that can use dual physical SIM cards:

 

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Continue reading

• GSM vs. CDMA
• Which phone will work with my carrier?
• Getting my Android device connected to my carrier
• Getting my iPhone connected to my carrier
• Locked vs. Unlocked
• Can't connect to the Internet from your phone?
• Is the phone 5G compatible?