In a recent blog post Ting announced they will start offering service on both GSM and CDMA networks starting in February 2015. They'll continue using the Sprint CDMA network, and based on the GSM coverage map they will be using T-Mobile for GSM with voice & text roaming on AT&T. You'll be able to use CDMA and GSM phones on the same account and combine usage if you have multiple people/phones. Looks like most unlocked GSM phones will work, T-Mobile phones wont need unlocking, but AT&T phones will. Some newer Verizon phones will also work. Ting has a page to check your phone here for BYOD availability. Here's a GSM FAQ page, and a GSM compatibility/unlocking guide. If you're switching to Ting: 1. They will pay a portion of your ETF if you're in a contract - 25% up to $75 of your Early Termination Fee. 2. You can also use this referral to save $25 when you join.