I don't use T-Mobile, but when I had to renew my contract with Verizon Wireless for 2 years, I asked them specifically about moving out of country before the contract was out, and the agent I spoke with told me that as long as I have proof of living out of the country (visa and a piece of mail with UK address), they would let me out of my contract without paying termination fees, so call T-mobile and ask!