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Best GSM SIM Card

Prepaid GSM SIM card plans starting at $10

Deal of the Month: Pure Talk 4GB for $18.75/mo* - See Deal
Tello Sim Card - Vertical
$5*per month
Powered by:T-Mobile
See Deal* Half Price for 3 Months
Pure Talk Sim Card - Vertical
$18.75*per month
Powered by:AT&T
See Deal* 25% Off for 3 Months
Mint Mobile Sim Card - Vertical
10GBLTE Data
$20*per month
Powered by:T-Mobile
See Deal* $60 for 3 Months Service
Ting Sim Card - Vertical
$10*per month
Powered by:T-MobileVerizon
See Deal* $5 extra per GB
US Mobile Sim Card - Vertical
$15per month
Powered by:VerizonT-Mobile
See DealFree Starter Kit with code: MSPUSM
Boost Mobile Sim Card - Vertical
$10*per month
Powered by:T-Mobile
See Deal* Double data when you bring your phone
Red Pocket Sim Card - Vertical
$19per month
Powered by:AT&TVerizonT-MobileSprint
Unreal Mobile Sim Card - Vertical
$10*per month
Powered by:T-Mobile
See Deal* $5 Off for 1 Month
Good2Go Mobile Sim Card - Vertical
$20per month
Powered by:AT&TT-Mobile
Mint Mobile Sim Card - Vertical
UnltdLTE Data
$30*per month
Powered by:T-Mobile
See Deal* $90 for 3 months Service
We currently have no deals for that combination, please change the filters

Disclaimer: MoneySavingPro is a free price comparison service but we do not provide service directly. We do our best to keep all the information up to date but there may be some discrepancies between the price you pay.

Big savings, no compromises
Nationwide CoveragePowered by the major networks
Bring your own phoneKeep your existing phone and number
4G LTE data speedsSame fast speeds as the big guys
No contractsFlexible and commitment-free
Customize your planOnly pay for what you use
Buy onlineNo need to visit a store
Best GSM SIM Card Hero
Switch and save $600 per year
Stop the Unlimited Data Plan Rip Off!
T-MobileT-Mobile 4G & 5GUnlimited*$70/mo$840/yr
Mint MobileT-Mobile 4G & 5G10GB$20/mo$240/yr
*Avg. data usage only 3-5GBSavings$50/moSavings$600/yr
Coverage CheckerFind great value plans with the best coverage in your area
Find cheap plans in your area
Lady shouting
3 Simple Steps To Switch & Save
Choose a Custom PlanDon't pay for data you don't use
Bring Your Own PhoneKeep your phone & number
Insert SIM & ActivateInsert your new SIM card & activate

GSM SIM cards

First things first, what's GSM? Global System for Mobiles, GSM for short, is one of the main technologies used worldwide to provide your phone with service. It's the tech that allows you to make calls and texts, wherever you are.

The other option is CDMA (Code Division Multiple Access). This network is used mainly in the US.

Which network you're on depends on your carrier. If you're currently with AT&T or T-Mobile, your cellular service runs on the GSM network. Whereas Verizon and Sprint use CDMA.

Looking to save money on your cell phone bill, but don't want to leave AT&T or T-Mobile's network? You're in luck.

There's a great range of MVNOs (Mobile Virtual Network Operators, if we're being formal) out there. These alternative carriers provide real bang for your buck. Your phone bill could come in at half the cost of going direct. Plus, you'll still have access to the network you trust.

GSM SIM cards make it easy to switch providers. You just take your old SIM out, then pop the new one in.

If you're currently with AT&T or T-Mobile you'll be able to bring your own phone. If you're not, don't worry. You can still get a cheap GSM SIM if you've got a phone on the CDMA network. Check out our guide on how to unlock your phone.

Switch & Save $600/yr - Calculate Your Savings

GSM SIM card benefits

  • Powered by the major US networks: GSM MVNOs provide wireless plans on the same major telecoms service you can trust. AT&T and T-Mobile are the two networks that run on GSM.
  • Save up to 50%: cut your cell phone bill in half and only pay for what you need.
  • No contracts: if you're not happy you can cancel at any time. No early termination fees.
  • Keep your phone: you can bring your own phone and keep your phone number with a hassle-free switch over. Saving even more money.

Best AT&T GSM SIM card

Pure Talk - 6GB Data* 25% Off for 3 Months
6 GB4G data
$22.50*per month$30/mo
Powered by: AT&TAT&T

AT&T vs Pure Talk Plan Comparison

Keep your AT&T phone, number & coverage: Save $562 per year

CarrierNetwork Coverage4G LTE DataPriceAnnual Cost
AT&TAT&T 4G LTEUnltd*$75/mo$900/yr
Pure TalkAT&T 4G LTE6GB$30/mo$338/yr
*Don't waste money on unlimited data - Avg. data usage is only 3-5GBSavings$45/mo$562/yr

Best T-Mobile GSM SIM card

Mint Mobile - 4GB Data* $45 for 3 Months Service
4 GB4G data
$15*per month
Powered by: T-MobileT-Mobile

T-Mobile vs Mint Mobile Plan Comparison

Keep your T-Mobile phone, number & coverage: Save $660 per year

CarrierNetwork Coverage4G LTE DataPriceAnnual Cost
T-MobileT-Mobile 4G LTEUnltd*$70/mo$840/yr
Mint MobileT-Mobile 4G LTE4GB$15/mo$180/yr
*Don't waste money on unlimited data - Avg. data usage is only 3-5GBSavings$55/mo$660/yr

What is a GSM SIM card?

All GSM phones use a SIM card. This tiny card is sent by your carrier when you sign up for their cell phone plan. It stores all your phone information, like contacts and personal data. It also makes it super easy to switch carriers.

If you're a frequent traveler, a GSM phone is ideal. You can purchase a local SIM for your unlocked device and save some extra dollars while you're away from home.

Depending on your phone, there are three types of SIM cards;

  • Standard SIM
  • Micro SIM
  • Nano SIM

The Nano SIM card is the most common and is used in newer smartphones like the latest Samsung Galaxy and Apple iPhones.

Don't forget to check which size SIM card your phone uses before signing up.

How to switch to a GSM carrier

Some carriers lock a cell phone to their network. But if you want to unlock your phone, in most cases it's an easy fix. Then, you can use it across any network.

If your current provider is one of the big four telecoms companies, AT&T, Verizon, T-Mobile or Sprint, you'll want to make sure your phone is fully paid off before switching.

With an unlocked phone, you can switch carriers hassle-free. With a low-cost alternative carrier, there's no contract. So, if you sign up and it's not what you expected you're free to switch.

Until a few years ago CDMA phones didn't use SIM cards, but they've now been built to use both CDMA and GSM. This makes it easier to change between the networks.

Things to figure out before you switch

    • How much talk, text and data do you need? With a low-cost carrier, you can tailor a plan to your needs. By keeping track of your usage you can save money and easily update your plan if needed. Use our free tool to check your average data usage.
    • Bringing your own phone? If your phone is unlocked and compatible with a GSM SIM card this is a great way to save money.
    • Who offers the best coverage? You can use our coverage map to find out which network and carrier work best in your area.

Which carriers are GSM?

Below is a list of carriers compatible with the GSM network piggybacking off AT&T or T-Mobile. If you're not sure which network is the best for your area, use our coverage map to check.

You'll be sent your GSM SIM card kit in the post with simple activation instructions to help you get started. If you're looking to bring your own phone, check on the carrier's website to make sure your phone is compatible.

AT&T GSM network carriers

T-Mobile GSM network carriers


CDMA and GSM technology was developed for old school 2G connectivity back in the early 90's. While the GSM network is used worldwide, CDMA is used mainly in the US.

But there's a newer technology in town, LTE.

As technology evolved, 4G LTE was created for data only. Still relying on GSM and CDMA for voice and text to fill in the gap when 4G was not available.

So because LTE phones need a SIM card, and the latest CDMA handsets now include SIMs, it's easier than ever to switch with a CDMA carrier.


There's a great selection of GSM SIM cards with low-cost carriers operating on T-Mobile and AT&T's network. Tailor them to your own needs and nail a great deal. Find out how much you could save switching your cell phone provider with our savings calculator.

If you're looking to bring your own phone and you're not sure if your phone is compatible make sure to check the carrier's website.

Still not sure? Why not have a look at our full selection of the best prepaid SIM cards for GSM and CDMA phones.

Joanne Wilkes
Joanne Wilkes

Jo has been helping people save money in the US and UK since 2012 in the internet, TV and cell phone industries. She loves helping people get the best value for their budget without the stress.


What is a GSM SIM card?

A SIM (Subscriber Identity Module) card is a removable memory chip that stores information unique to the cell phone user.

What does a GSM SIM card do?

Cell phones need a SIM card in order to connect to a phone network in order to make calls.

How do I remove a GSM SIM card from my phone?

The position of the access cover varies by phone but it’s usually on the side of the device. To remove the SIM card, use an eject tool or paper clip and push to release the SIM card tray.

How do I insert a GSM SIM card into my phone?

The position of the access cover varies by phone but it’s usually on the side of the device. Place the new SIM card into the SIM card tray and slide the tray into your phone.

Prepaid SIM Card Comparison