Does the iPhone 5 support 4G / LTE cellular data?
Yes. Apple has officially jumped on the LTE bandwagon, and their latest smartphone, the iPhone 5 offers full LTE compatibility (at least on US carriers AT&T, Verizon, and Sprint).
Some expected the iPhone 4S to support the LTE standard, however Apple waited almost one year to incorporate the technology. Product designers included a single chip for all of the radio functionality to save space. Despite the fast LTE download speeds, the iPhone 5 suffers no reduction in battery life over the iPhone 4S.
US carriers are quickly building out LTE capabilities on their networks nationwide.