Passengers landing at Kilimanjaro International Airport (JRO) will encounter a new process for visas on arrival. In order to save time, it is recommended that you obtain a e-visa, or visit the Tanzanian Diplomatic mission closest to you at least 6 - 8 weeks pre arrival. 

You can visit this e-visa portal (link here) The immigration services have advised that most visas are issued within 2 to 3 weeks of the application via the e-visa system.

Look for a government link or TTB source please as the link