The ambitious low-cost carrier is also planning to set up in Nairobi, Kenya, once the A319 aircraft is approved for use from the airport.
The group has already signed a lease for its first Airbus passenger jet, which will arrive in Dar es Salaam next month.
Recruitment of crew and ground staff is already “well advanced”, FastJet said.
The company plans to become Africa’s leading budget carrier by offering flights for as low US$20 one-way, excluding taxes and charges.
FastJet Chief Executive Ed Winter said: "Our initial focus will be on East Africa with the airline's first base at Dar es Salaam, Tanzania, where the A319 aircraft has already been approved by the Tanzania Civil Aviation Authority.
“This will be followed by a second base in Nairobi, Kenya, once the A319 is approved there. We look forward to bringing a great, reliable and affordable service to the people of East Africa."
Once established in East Africa, FastJet has plans to launch in Accra, Ghana and Luanda and Angola.
The business is being developed with the help of easyJet founder Sir Stelios Haji-Ioannou, who is both a shareholder and director of the company.
The eventual aim is to create an airline carrying 12 million passengers a year using the low-cost blueprint patented in Europe.
It is an undertaking that will require a 40-strong fleet, but which would create a US$1 billion turnover business.
City analysts say the combination Haji-Ioannou and 73.7 per cent shareholder Lonrho (LON:LHRO) ticks all of the boxes required to run a successful no-frills airline in the region.
Lonrho brings the African knowledge; the new management under Ed Winter brings hands-on operational experience of running a low cost carrier; and Stelios brings credibility and supplier relationships and Fly540 provides a developed platform.
The market it addresses is also potentially huge and currently underdeveloped.
Africa is the fastest growing continent in the world, but airline capacity is just one seat per year per 13,000 people.
The US has 2.5 seats per person, while for the African market to grow to the size of Europe’s would require an extra 1.7 billion seats.