Apple iPhone SE
Sprint - Model A1662 or A1723?
sprint does allow global roaming through their own version called sprint global roaming. link is here http://www.sprint.com/landings/international- value-roaming/ but i can only assume it uses edge or 1x, not sufficent for voip but if you do wifi calling, it may be possible to do free calling.
it is also possible to get it unlocked but someone already listed the link to the unlocking policy also try the apple store
the other choice is getting a cheap temporary phone that you can get unlimited texts with global roaming and then use the cheap unlocked phone with the countries sim to call them back.
i have the international roaming plan as well as google voice for international just in case but i use the mot...
A1723 is the only model with LTE 41. That's the Sprint version. You should get that one. It has all of the other bands you need for decent global roaming.
Whether you can get it unlocked for local SIM cards is something to take up with Sprint. Their unlocking policy is here: