Will a Samsung Galaxy S3 4G/LTE bought in the US work or be made to work on UK 4G? I'm researching which phone to buy next and have mostly decided on a Samsung Galaxy S3.  I'm on T-Mobile in the UK, which will probably transition to everything-everywhere in short order, who are launching a 4G service.

I'd like to get the US variant of the phone because it is built with 2Gb of RAM and a 1.5GHz processor, as compared to the UK's 1Gb of RAM and a 1.4GHz processor.

I've read that the carrier frequencies for US 4G/LTE are different from the UK's.


Is that true?
If it's true, can the US variant be persuaded to work in the UK, 4G-wise?  I'm not shy of flashing custom ROMs and so forth.


(I'm assuming that it will work without issue on 3G?)
Is that true?


Yes, this is true. The USA is currently using the 700, 800 (Sprint only, I think), 1700 and 1900 MHz bands for LTE service, whereas European providers are using 800, 900, 1800, and 2600 MHz (Wikipedia).


  If it's true, can the US variant be persuaded to work in the UK, 4G-wise? I'm not shy of flashing custom ROMs and so forth.


No. The frequency limitation is not set by the software - it's the antenna. Flashing custom ROMs will not allow you to access frequencies that the antenna is physically unable to support, so there's nothing you can do short of modifying the hardware.


  I'm assuming that it will work without issue on 3G?


This could potentially depend slightly on which specific variant you want, I suppose. The AT&amp;T one supports 850, 1900, and 2100 MHz frequencies, the T-Mobile USA one also supports 1700 on top of the other three. According to this table, T-Mobile UK uses the 2100 MHz band, so either should be compatible with their 3G service in that case.