Can I keep my unlimited data plan with the iPhone 5?
Sprint is the only major US carrier offering the iPhone 5 with unlimited data plans. This applies to new and existing customers.
AT&T and Verizon have both allowed some loyal iPhone customers to keep their unlimited data in the past. Will these grandfathered data plans be allowed on the LTE iPhone 5?
The answer is yes, with some caveats. When it comes to AT&T, your chances of keeping an unlimited data plan with the iPhone 5 are better if the phone is purchased and configured at your local AT&T store. Pre-ordering or buying online may not keep your existing data plan, especially if you change plan details using the website. Beware, once the grandfathered plan is gone, it's gone!UPDATE: Some AT&T users report that their grandfathered data plan appeared automatically when pre-ordering from Apple's website.
Verizon automatically drops unlimited plans when a new contract begins. This means no more grandfathered data plans. If you are interested in keeping unlimited data with Verizon, you must purchase an unsubsidized iPhone 5 at full price (a $400 premium) . Do the math, because although it may cost more up front, over a two year period the older data plan could save you money compared to current offerings.