The US does a lot of things differently: voltage, plugs and the mobile (here often called: cell[ular]) phone system too. This leads to a lot of errors and confusion when you come from a different part of the world. Here is a short guide to avoid disappointments.
This article applies to the 50 states and the District of Columbia of United States of America (USA). It's valid for all of the continental mainland and the islands of Hawaii as well. There, the same operators are on the air forming one common network without roaming fees. This is partly true for Alaska, Puerto Rico and the US Virgin Islands too, but additional operators offer mobile services there shown in own Puerto Rico (incl. US Virgin Islands) and Alaska articles. Other US overseas territories where different providers operate are featured in separate articles like these of Guam or Samoa.
The USA has 3 national mobile networks:
- * Verizon
- * AT&T Mobility
- * T-Mobile US
There used to be a fourth provider, Sprint, but was merged with T-Mobile in 2020. A new fourth provider will be established by the satellite pay-TV company Dish.
This is supplemented by small regional networks operating in limited areas. Through domestic roaming agreements they are partly available to prepaid and postpaid customers of the big 3 providers too.
There are also many MVNOs using their networks, but the "Big 3" also own the bigger MVNOs in the country. Verizon owns TracFone (and its sub-brands like Straight Talk, Net10, etc.), AT&T owns Cricket Wireless, and T-Mobile owns Metro by T-Mobile (MetroPCS).
CDMA- vs. GSM-based networks
In the US, two different mobile network standards operated which were not compatible until 4G/LTE had arrived. CDMA technology, used in very few countries such as South Korea & Japan, was employed by Verizon and Sprint. GSM technology was employed by AT&T and T-Mobile. This was historically a problem, as these standards were completely incompatible with each other. Recently, with the advent of 4G LTE and especially 5G, this has changed since both CDMA and GSM are being phased out and are no longer relevant. Since Verizon was a historically CDMA network and operated differently, on this wiki most information on Verizon was separated into this sub-article "CDMA in the US". Verizon, however, can be treated the same as other carriers since, for new customers, they are solely a LTE / 5G NR network now.
- in 2G Verizon uses CDMA, while T-Mobile uses GSM. AT&T operated GSM until its shutdown in 2017.
- in 3G Verizon uses EVDO, while T-Mobile employs UMTS-based technology. AT&T operated UMTS until its shutdown in 2022.
- in 4G / "5GE" all operators employ LTE-based technology only.
- in 5G all operators employ 5G NR-based technology only.
The gap between the "Big Three" networks has narrowed over the years. Verizon and AT&T have always been the bigger networks with the most nationwide coverage, and T-Mobile has caught up and is now a strong competitor to the other two networks. However, coverage does not always equal fast data speeds, and will greatly vary based on your area. You can use the coverage maps listed further down below to compare for yourself in a specific area, but beware that these maps can be misleading at times. The FCC (Federal Communications Commission) has created a more accurate map for 4G LTE that you can view here, but it is slightly outdated.
However, none of this will matter if your phone doesn't support the network, or if the network doesn't support your phone. In some cases you will not have a choice, and the following information will explain why.
Compatibility and frequencies
For international devices, you must compare the frequencies of your device with the frequencies offered by the 3 carriers as there are still a lot of incompatibilities with regard to devices from outside the US. For major phone models check against this list shown here. Keep in mind that some models with the same name are sold as different versions in the country versus Europe/Asia, or are not sold at all in the US. This can be a major problem, many popular phones in other countries such as Xiaomi might lack critical frequencies used by American carriers.
For carriers without a GSM / UMTS fallback (which at this point will only be T-Mobile) your phone must support VoLTE (Voice over LTE) to make voice calls or you can only use VoIP apps like WhatsApp, WeChat, Skype, etc. for voice.
AT&T requires not only VoLTE, but has a whitelist of approved devices. This is a network-wide policy, affecting not only AT&T but all MVNOs that use their network, and even postpaid customers. This severely restricts AT&T or its MVNOs as an option for most outsiders, with a notable exception of iPhones 6 and later, which according to their whitelist should work even if it is an international variant.
Verizon also has a whitelist, but they are far less strict in enforcing it. You may not be able to activate an "incompatible" phone, but if you activate the SIM in a whitelisted phone, such as a US model iPhone, it is possible to swap the SIM back to your phone and use it on the network.
T-Mobile has the least restrictions on activating devices - as long as it supports VoLTE you should be able to activate it, and use it on their network.
AT&T's policy won't affect you when you use a roaming SIM card from overseas in the US, but only if you want to activate a local US SIM card on your phone. Nevertheless, without any 3G networks left in the country, and limited 2G network support, your phone will ideally need to support VoLTE if you want to receive or place usual voice calls also when roaming with a foreign SIM card on US networks. Since AT&T no longer has GSM or UMTS, which most carriers roam on, this significantly affects international roaming onto their network (especially to use voice and SMS.)
2G/GSM (GPRS, EDGE)
For 2G, you need a phone that supports 1900 MHz bands. AT&T has shut down its 2G network nationwide as of January 1st, 2017. This leaves T-Mobile as the only player for 2G. For T-Mobile you need to have at least a 1900 MHz compatible device as it's their only frequency.
While T-Mobile seems to have indefinitely postponed their GSM network shutdown, it should not be considered as reliable for primary use. In many areas, especially metro areas, 2G will be nearly unusable for data - T-Mobile has reduced GSM spectrum to a very small amount.
On 2G you can only get EDGE with slow data speeds up to 200 kbps - in some cases data will not work properly at all. Either way, if you want to use 2G for roaming, for example in dual-SIM phones, be sure that your roaming partner supports T-Mobile in the US or you will be shut out.
Verizon's legacy CDMA / EVDO network will shut down at the end of 2022, leaving no major CDMA networks in the US.
3G/UMTS (HSPA, HSPA+)
Both carriers market(ed) their HSPA as "4G" until they were shutting down their networks.
AT&T began shutting down their 3G / UMTS network on February 22, 2022. Their 3G network operated on 850 MHz and 1900 MHz. While coverage is still available in some markets, it is subject to shut down
T-Mobile will shut down their 3G / UMTS network on July 1, 2022. They operate on 2100 MHz and 1900 MHz, but this will depend on your region. In fact, some areas had already shut down 3G
Things get more complicated with 4G.
AT&T operates 4G mainly on 700 MHz, which is Band 12 and 17. They also operate on 850MHz/B5 (being refarmed), 700MHz/B14, and additionally Bands 29 and 46 (700 & 5200 MHz) are used to supplement downlink. Band 30 and Band 66 are used for capacity.
In 2019, they started to market aggregated LTE / LTE-Advanced as "5G E" (stylized as 5G E), similar to how Claro in Brazil and other countries advertised it as "4.5G". This is not real 5G, rather based on 4G and better known as LTE+. On iPhones and supported Android phones, it will display the network as 5G E instead of LTE+, 4G+ or 4G LTE like it would on other devices.
T-Mobile's 4G is mainly operated on 700 and 600 MHz, Bands 12 and 71. They call it "Extended Range 4G LTE". They also operate 4G on Bands 2, 4, 5, and 66. They have a coverage map which even shows all frequencies used for LTE here.
Verizon operates mainly on 700 MHz Band 13, along with 1700 / 2100 MHz (B4/66) and 1900 MHz (B2). For additional capacity they use Bands 5, 46, and 48.
Be aware that the 700 MHz frequency used in the US is on bands 12, 13, 14, 17 and 29. These bands are all incompatible with the 700 MHz that is going to be employed or already in use in Europe, Asia, Australia and Latin America on band 28 (B28) because of different up- and download spectrum.
For Verizon and T-Mobile, if your device is missing any of these bands, you may experience gaps in coverage. This would be most noticeable on T-Mobile's Band 71, which is used for a lot of rural and indoor coverage. Keep this in mind when using an international or old device.
LTE compatibility of non-US devices
Unfortunately all mentioned 4G/LTE frequencies are hardly used for 4G anywhere else in the world and a phone from outside the US might be compatible with only a few of the frequencies used. The latest Apple and Android phones tend to have a much broader range of 4G/LTE bands, including the necessary US LTE bands. Check the specifications for your phone model number. The same applies to routers, tablets and modems, which are hardly available for US and overseas markets at the same time.
As an alternative, locally cheap disposable phones are sold (colloquially referred to as burner phones) at major retailers such as Walmart, Best Buy and Target. A cheap smartphone with LTE will cost anywhere from $20 to $100. It will work only in the US and nowhere else and is likely to be locked to the provider. On the flip side, most routers and modems are priced higher in the US than similar models in Asia or Europe. For AT&T, this may be your only option if you want to use their network and don't have a supported phone yourself. They are guaranteed to work on their network.
Generally, in most cases phones locked to a specific network usually work on MVNOs using that network, but not the other way around. For example an AT&T locked phone will work on Cricket, but a Cricket phone won't work on AT&T unless unlocked.
The 3 national providers AT&T, Verizon, T-Mobile [& Sprint] all launched their 5G networks in 2019. All of them have launched 5G for prepaid subscribers on their main prepaid network, and their main MVNOs.
Low-band, Sub-6GHz 5G is marketed as 5G Nationwide by Verizon, and 5G Extended Range by T-Mobile. Mid-band and high-band 5G is marketed as 5G+ by AT&T, 5G Ultra Wideband by Verizon, and 5G Ultra Capacity by T-Mobile. Unfortunately, for prepaid Verizon requires a more expensive plan to access 5GUW, while AT&T requires a specific plan to access 5G at all. On the other hand, even T-Mobile's cheapest plans can access 5G.
Note that it is much different for MVNOs - some cannot access 5G, others will usually only support low-band 5G, and a few can access mid/high-band with a specific plan.
Just like 4G, 5G frequencies are different to the ones used in other countries. But again, lower-end "burner" phones with 5G are now available starting from around $200. However, unlike 4G LTE, 5G is considered an optional and premium feature by AT&T and Verizon, so it may not be worth the investment.
Not all frequencies are available in all locations.
|2G (GPRS, EDGE)||-
|3G (UMTS, HSPA+)||-
|2100 MHz, 1900MHz
|4G (LTE, LTE+)||1900, 1700 / 2100, 850, 700, 2300, 5200 MHz
B2, B4, B5, B12/17, B14, B29, B30, B46, B66
|1900, 1700 / 2100, 850, 700, 2500, 5200, 3500, 600 MHz
B2/25, B4/66, B5, B12, B13, B41, B46, B48, B71
|1900, 1700/2100, 850, 700, 5200, 3500 MHz
B2, B4/66, B5, B13, B46, B48
|5G NR Sub6||1900, 850 MHz
|1900, 850 MHz
|5G NR Mid-band
|5G NR mmWave
|24 GHz, 39 GHz
|39 GHz, 28 GHz
|39 GHz, 28 GHz
The following characteristics may be taken for granted for US residents and frequent visitors, but pose a challenge for newcomers:
Prices and taxes
As usual in the US, all prices mentioned below are without taxes. In most states, you need to add sales taxes of up to 10% to the stated prices. This applies to starter packs and top-up vouchers, locally called refill cards, sold over the counter. Even online top-ups on the websites of the providers are taxed additionally. A reliable workaround for many providers is the 3rd party top-up site of Callingmart. For whatever reason, they don't charge any tax and only a minimal fee of up to 2% on some operators, which can sometimes be waived by using promotional codes.
When it comes to phone calls, the US is unique in two respects. First, the receiving party gets charged for taking a phone call (either at pay-as-you-go rates or deducted from the receiving party's bundled minutes) and therefore if a receiving party does not have any credit remaining, the call will not be connected (or if the receiving party runs out of credit whilst the call is in progress, it will be terminated immediately). Second, the call is charged from the moment you dial, not the moment the other party picks up, thereby rendering the first minute effectively as a connection charge so ensure you have good cellular coverage and be careful when dialing.
In the US, a data bundle or package is normally referred as a plan. This is because most data plans or packages require a monthly base plan that already includes a data allowance. More data can often be added as an add-on. On the other hand, this means that it's hard to stop the monthly base rate while you are out of the country and can't use your plan. The only way is to let your account balance fall below the recurring base rate (while auto-pay is disabled), so it can't be automatically renewed. But thus your plan will be suspended after a few months and your number will be lost.
BYOD and BYOP
The simple fact that you already have an unlocked mobile device capable of US frequencies and only need a new SIM card (and a 'plan', see above) from the provider is often called either BYOD or BYOP in the US. It stands for "bring your own device/phone" and, as explained earlier, can be complicated when trying to bring an international phone.
Plugs and voltage
All power adapters for mobile devices can cope with both 110 and 220 Volts nowadays, but you may check beforehand whether "110 V" is written on it. So only the US flat-pin power plug can be a challenge for visitors from overseas. All round-pin plugs and even Australian flat-pin plugs need an adapter to fit. A 2-pin adapter is sufficient. These are available for around $1-$2 in cheap Chinese-owned stores, but some travel accessories shops might want to charge you $20+ for a set of these small plastic parts. If you don't go to a city with a Chinatown, you might want to bring it from your country or buy it on for example eBay beforehand.
Another thing you have to consider is that even the most basic replacement USB cable in the USA can wildly vary in price, especially in tourist areas. While cheap cables may be available in convenience stores, gas stations, etc., they may also sell expensive cables instead that can cost over $10! So make sure you bring (and don't lose) your own charging cable from home.
As long articles are hard to navigate on mobile devices, this US article is now split into 3 sub-articles according to network provider: AT&T, T-Mobile and its respective resellers as well as Verizon from the perspective of a GSM device holder.
Click on the logo below to choose network and relevant sub-page: