Using a European (GSM) cell phone in the US

Not all European GSM phones work in the US (regardless of the SIM card). In fact I tried to use one of my GSM flip phones (bought new in 2015) in New York and it just said “no network”, it didn’t even have the possibility for emergency calls.

Part of the relevant information is here on wikipedia: https://en.wikipedia.org/wiki/GSM_frequency_bands

Europe uses GSM 900 and 1800 (“dual band”).

America (not only the US. Also Canada, South America, Central America) mostly uses GSM 850 and GSM 1900.

Smart phones are typically quad band phones. I assume the manufacturers don’t want to bother with different models for different parts of the world, or nowadays, the possibility to use your smart phone everywhere is far more important than with “cheap” phones that could only text and phone – after all for these services you also need a decently priced plan, or might just be unavailable (time zone difference, vacation, …) or get a throw-away phone in the country you’re visiting.

You already collected the relevant information about what GSM standards your phone can do, and in fact all relevant ones are covered.

Yes, GSM phones will work in the US, either on GSM carriers (at&t, T-Mobile) or their resellers (MetroPCS etc.) or MVNOs (Virgin Mobile, LycaMobile etc.)

To solve the dilemma of international roaming for call/text/data, get a dual-SIM GSM phone and install both a US and local SIM. These are common (OnePlus, Samsung, Huawei, Xiaomi, Honor etc.) Obviously, when you’re in Europe, turn off data roaming on your US SIM (and restrict or disable bandwidth-hungry apps), and vice versa.

Btw T-Mobile postpaid allows cheap international roaming and free international texts in most foreign countries. As long as the T-Mobile postpaid account has been active domestically in the US for the preceding n [*] months, and the foreign usage does not exceed fraud threshold. [*] T-Mobile reps have quoted me numbers anything between 1-6 months.

This is an excellent site I’d visited to figure out which SIM cards would work on my parents’ Mi A1 phones in Canada – https://willmyphonework.net/.

If you are looking for roaming, it might be expensive. You are probably better off getting a US SIM (T-Mo, Ultra Mobile etc.) and using it for the duration of your stay. Your choice, of course, but just a suggestion.

In addition to the other answers:

1. Check the roaming charges for your provider/subscription. They can be extraordinarily high. The biggest issue is data, as your phone can use a lot of data without you even noticing or even doing anything actively on your phone (background updates of apps, e-mail…).

   Providers often given data rates using units such as MB or even KB. 0.10 €/MB doesn’t seem much, but when you use a few hundred MB per day, that easily adds up to hundreds. Some others will include calls and data for some destinations, but there may be a cap, or a threshold beyond which they start charging per MB.

2. If you decide you definitely want to be able to use voice & data while in the US:

   • check that international roaming is enabled with your mobile provider. Some enable it by default, some don’t. Some may require a deposit or something similar to enable it. It may vary depending on your contract.
   • check for any relevant “add-ons” which may reduce your costs.
   • check that your phone has roaming and/or data roaming enabled (the two settings may be in different places).
   • monitor your usage.

Many years ago, it was highly unlikely that a European cell / mobile phone would work in the US.

More recently, but still quite long ago, your phone might work if it supported the US bands.

In both cases, the answer might have varied from state to state or city to city.

These days, you are unlikely to experience a problem. Phones are now much more standardised than in the early days. I have not experienced a problem roaming in the US for a long time.

To be absolutely sure you would need to check with your current service provider and research ones in your destination area.

I suggest that you check roaming charges carefully: they might be very high, especially for data. You might want consider getting a local SIM card. How easy this is seems to vary a lot.

yes your phone will work also in the US.
Regarding internet: you should have the option for data roaming active, otherwise it will not connect to the data network.