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Best GSM SIM Card

Prepaid GSM SIM card plans starting at $10

Nationwide Coverage4G LTE Data SpeedKeep Your Phone & NumberNo Contract
Best 3GB Plan
3GB LTE Data
$5* per month
Powered by:AT&TVerizonT-MobileSprint

See Deal

* $14 Off in 1st Month
Best No Data Plan
0GB LTE Data
$10 per month
Powered by:VerizonT-MobileSprint

See Deal

Best 4GB Plan
4GB LTE Data
$18.75* per month
Powered by:AT&T

See Deal

* 25% Off for 3 Months
Best Unlimited Plan
Unltd LTE Data
$30* per month
Powered by:T-Mobile

See Deal

* $90 for 3 Months Service
Check Coverage
It's never been easier to switch your carrier & saveSave up to $600 a year
Starting at$5*
Powered by:AT&TSprintT-MobileVerizon
1GB Data* $5 Off in 1st Month1,000Unlimited1GB$5*
3GB Data* $14 Off in 1st MonthUnlimitedUnlimited3GB$5*
10GB Data* $25 Off in 1st MonthUnlimitedUnlimited10GB$5*
22GB Data* $35 Off in 1st MonthUnlimitedUnlimited22GB$5*
Unlimited DataUnlimitedUnlimitedUnlimited$60

US Mobile GSM SIM Card

Free Starter Kit with code: MSPUSM
Starting at$10
Powered by:VerizonT-Mobile
Unlimited Talk & TextUnlimitedUnlimited0GB$10
2.5GB DataUnlimitedUnlimited3GB$15
10GB DataUnlimitedUnlimited10GB$30
Unlimited DataUnlimitedUnlimitedUnlimited$40
Starting at$10
Powered by:SprintT-MobileVerizon
Unlimited Talk & TextUnlimitedUnlimited0GB$10
5GB DataUnlimitedUnlimited5GB$25
Unlimited DataUnlimitedUnlimitedUnlimited$45

Good2Go Mobile GSM SIM Card

* Double Data for 3 Months
Starting at$10
Powered by:AT&T
Unlimited Talk & TextUnlimitedUnlimited0GB$10
1GB DataUnlimitedUnlimited2GB$15*
3GB DataUnlimitedUnlimited6GB$20*
5GB DataUnlimitedUnlimited10GB$30*
10GB DataUnlimitedUnlimited20GB$40*

Pure Talk GSM SIM Card

* 25% Off for 3 Months
Starting at$15*
Powered by:AT&T
2GB DataUnlimitedUnlimited2GB$15*
4GB DataUnlimitedUnlimited4GB$18.75*
6GB DataUnlimitedUnlimited6GB$22.50*
10GB DataUnlimitedUnlimited10GB$26.25*
20GB DataUnlimitedUnlimited20GB$33.75*
Unlimited DataUnlimitedUnlimitedUnlimited$41.25*
Starting at$15
Powered by:T-Mobile
3GB Data* $45 for 3 Months ServiceUnlimitedUnlimited3GB$15*
8GB Data* $60 for 3 Months ServiceUnlimitedUnlimited8GB$20*
12GB Data* $75 for 3 Months ServiceUnlimitedUnlimited12GB$25*
Unlimited Data* $90 for 3 Months ServiceUnlimitedUnlimitedUnlimited$30*
Starting at$15
Powered by:AT&T
3GB Plan* $45 for 3 monthsUnlimitedUnlimited3GB$15*
8GB Plan* $60 for 3 monthsUnlimitedUnlimited8GB$20*
12GB Plan* $75 for 3 monthsUnlimitedUnlimited12GB$25*

h2o Wireless GSM SIM Card

* 25% Off for 3 Months
Starting at$15*
Powered by:AT&T
2GB DataUnlimitedUnlimited2GB$15*
6GB DataUnlimitedUnlimited6GB$22.50*
15GB DataUnlimitedUnlimited15GB$30*
Unlimited DataUnlimitedUnlimitedUnlimited$37.50*
Starting at$16
Powered by:T-MobileSprint
Unlimited Talk & TextUnlimitedUnlimited0GB$16
1GB DataUnlimitedUnlimited1GB$19
3GB Data for 12 Months* $240 for 12 MonthsUnlimitedUnlimited3GB$20*
2GB DataUnlimitedUnlimited2GB$23
6GB Data* $300 for 12 MonthsUnlimitedUnlimited6GB$25*
5GB DataUnlimitedUnlimited5GB$29
Unlimited Data* 20% Off All Monthly PaymentsUnlimitedUnlimitedUnlimited$39*

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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.

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It's never been easier to switch your carrier & save
Stop the Unlimited Data Plan Rip Off!
T-MobileT-Mobile 4G LTEUnlimited*$70/mo$840/yr
Mint MobileT-Mobile 4G LTE8GB$20/mo$240/yr
*Avg. T-Mobile unlimited plan customer uses 5GBSavings$50/moAnnual Savings$600/yr
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&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 - 3GB Data* $45 for 3 Months Service
3 GB4G data
$15*per month
Powered by:T-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 LTE3GB$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.

What SIM card size do I need?

There are 3 SIM card sizes: standard, micro and nano SIM. All phones released since 2014 (Apple iOS and Android) now support the nano SIM card. Older phones will require either the standard or micro SIM card but most MVNOs will send out a SIM card that can be adapted to all 3 sizes.

How much does a GSM SIM card cost?

The cost of the GSM SIM card varies between carriers. Typically, the cost is $4-5 but some carriers offer free SIM cards with their prepaid cell phone plans.

Where can I buy a new GSM SIM card?

You can purchase a GSM SIM card online or in a cell phone or electronics store.

How do I activate my new GSM SIM card?

Activating your new GSM SIM card is straight forward. When you receive your SIM card, contact the carrier and they will talk you through the activation process.

How do I configure my new GSM SIM card?

You may need to adjust the APN settings on your phone. The carrier will help you with this during activation.

Will my device work with a GSM SIM card from another carrier?

Any unlocked device with a GSM SIM card slot should work. However, phone compatibility does vary by exact device and carrier, so it’s important to check that your phone is supported on the carrier website, prior to ordering a new SIM card.

Can I keep my phone number when I switch the SIM card?

Yes, it’s simple to transfer your phone number when you bring your phone to a new carrier.

Do these low-cost carriers provide cell phone coverage in my area?

Although you may not be familiar with some of the carriers, all MVNOs are powered by one or more of the 4 major networks (Verizon, T-Mobile, AT&T and Sprint). Therefore, you should not experience any loss in service.

Prepaid SIM Card Comparison

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