Update: Sprint adds 36 more Countries & Destinations to its Global Roaming Plan
Sprint now covers more than 110 destinations globally and these recent additions as of January 8th, 2016 makes a huge improvement for SE Asia & Europe. I experienced issues with using data service while in Indonesia which resulted in Sprint advising they only offer voice and SMS coverage which is a bit misleading. Be sure to double check the country prior to your travels.
With the introduction of Sprint Open World, you can now get 3G data speeds for $30/GB which is an excellent price compared to other carriers. If you just want unlimited 2G data speeds then stick with the Sprint Global Roaming Plan.
New Global Coverage Map:
Previous Global Coverage Map:
The new countries and destinations include:
Republic of Malta