As I explained in a post elsewhere in this forum: http://www.droidforums.net/forum/ve...n/244238-verizon-will-losing-me-customer.html I need to be able to use a 3rd party SIM card when traveling internationally, AND also tether my phone while on that SIM card. This is something I can no longer do with my Verizon Razr Maxx, so I'm looking to switch. I like that T-Mobile is month-to-month. I like that the S4 seems to be able to accept foreign SIMS. What I don't know is whether T-Mobile's version of Android needs to connect back with the T-Mobile mothership for tethering entitlement checks. If so, then I'm in pretty much the same boat with T-Mobile as with Verizon. Does anyone here know whether I can tether on a Samsung Galaxy S4 from T-Mobile while using a 3rd party SIM?