Can I use my iPhone from Verizon with Sprint?

A while back, I was on a family plan with Verizon. My Dad slacked off on paying the phone bill, (I gave him my portion of the bill every month) so I no longer have service on my iPhone.

Is it possible that I can use my current iPhone with Sprint?

If not, is it possible that I could start my own contract with Verizon since I'm over the age of 18?

Nope. Sprint can't activate Verizon phones and vice versa. And yes you can get on your own plan with Verizon. They are a bit spendy though. Expect to be paying around $100 per month. Sprint, with the proper know-how, will cost around $75 or so.

Verizon Iphones can't be flashed to Sprint. Sprint won't allow it. And vice versa---Sprint Iphones can't be used on Verizon. Verizon won't allow it…

as for using the same iphone on a new account… Its possible, but the ESN of the Iphone would have to be CLEAN… If the first account holder failed to meet contract and bill obligations, then the ESN would be locked to that 1 account, thus making the phone non-flashable and non usable to anyone on Earth, thus making the iphone---a very expensive Ipod-touch--until the original account holder meets All contract and bill obligations