Theres alot of incorrect information here. The latest Sprint phones using sim cards ARE ABLE to use T-Mobile and AT&T as long as GSM is in the hardware. I dont own the S5 but for those blinding others with frequency talk I'm tired of seeing, read it and weep:
Sprint S5 supports GSM. Now of course no LTE on T-Mobile due to the lack of the 1700 frequency,
but your 4G will be fine. Depending on where you live, you may not even care about LTE over 4G.
Sure, Sprint locks the darn thing up to avoid it getting into the hands of other domestic carriers, but
just as the Sprint Note 3 and my Sprint LG G2, a workaround has been invented. For the G2 it was as
"borrowing" the stock T-Mobile LG G2 firmware and tweaking it to boot up on our LS980. We have
about 3 different tastes of working unlocked roms, not only sticking to T-Mobile, but other carriers
reported working such as Metro PCS and AT&T. So my guess is that the S5 may need a similar
treatment, nobody wants Sprint honestly. The first 14 days (brought in my own LG Optimus G LS970)
I was with them service was glorious here in NYC. But after the 14 day "trial period" ended I was
DAMNED into horrible service, constant 3G instead of 4G, etc. Thanks to refusing to make payments
due to the disgusting service, my GS4's IMEI is basically crap, so I sold it in the same week I got it.
I should have never swapped it out for the LG OG...
Honestly, I'll thank every OP I see that "unlocks" the Sprint version of any phone for domestic GSM
use. Their silly Sprint Spark is useless, why introduce something new when they dont even have full
4G coverage here in the USA? And their agents sound like "AI" controlled cyborgs: "Oh we're sorry to
hear that, your zone is scheduled to be recieving 4G soon." Yeah right. I feel sorry for those who suffer
in other states.
ANYWAYS sorry for drifting off topic. The recap here is that the Sprint S5 IS capable of domestic GSM with some modding.
And also that I hate Sprint.