Under T-Mo USA's Simple Choice Plan - to keep costs down and without a contract, you can downgrade to the $40 monthly plan with unlimited call & text and 500 MB of 4G data - excess will be at 2G speed. Then, switch back to the $50 plan with 1GB data & int'l roaming.

Or, for Maps, Translate & simple email checking only (and no voice calling) - consider T-Mo's Mobile Internet (data only) Plan, the latest promo offer good for rest of 201 is for just $20/mo + taxes/fees - up to 3GB of 4G LTE data, excess will be 2G speed. There is NO contract so basically month to month and int'l roaming is included - tethering is possible with the proper setup on your device. BUT, and a big but, the CAP or limit on roaming data is just 50 MB, in the fine prints - which isn't a lot at all. http://www.t-mobile.com/cell-phone-p...tab-navigation

My domestic T-Mo prepaid line has 10GB of 4G data for $30/mo. with UNLimited texting & 100 minutes at home only. On a rooted Nexus 5 with a custom Rom, tethering is great & fast even when it's in 3G only mode, except that it doesn't roam international. Nexus 7 and other Android devices tether without problems with it (thanks to XDA-Developers ... with minor APN settings change & text editing, etc.) but I just can't seem to get the iOS devices to connect properly to it.

With an unlocked iPhone5 overseas, you might be better off getting a local SIM card with better rates for accessing & using faster mobile data as T-Mo USA's roaming plan will throttle you back to 2G or Edge speed - especially if your business travel will take you back to the same countries over a relatively short period of time. To get the most speed out of the rest of the world's GSM 3G/HSPA+ and/or 4G services, something like the Moto G running Androids (global and non-USA specs') would be most flexible to matching the oversea carrier's bands - priced as low as $179 plus there's a dual Sim model available oversea only. I have not heard or read of anyone successfully getting 3G speed yet with T-Mobile's plan overseas, and if they manage to do it, keep it to a whisper mode. T-Mo's network design is to scale it back to 2G speed once the threshold or limits are exceeded, especially while roaming & beyond what we can "tweak" on our devices.