Fastjet expects to launch its first international flights to Uganda, South Africa and the Comoros "in the next few weeks".
The Stelios Haji-Ioannou-backed carrier began operating domestic Tanzanian services from Dar es Salaam to Mwanza and Kilimanjaro in November 2012.
Entebbe in Uganda, Johannesburg in South Africa, and Moroni in the Comoros Islands are now expected to become the first international destinations, it says in a statement.
Fastjet had previously identified Nairobi and Mombasa in Kenya, Kigali in Rwanda, and Juba in South Sudan as routes of interest.
The company initially planned to open a second operating base in Nairbo in the first quarter of 2013. But it expedited plans for a South African base after negotiating a potential takeover of Johannesburg-based 1time Airline, which is in provisional liquidation.
Its goal of becoming a point-to-point pan-African carrier also envisages the launch of two west African bases in Accra, Ghana and Luanda, Angola.