Star Alliance airlines have dropped ticket prices to $575 for San Francisco to Nairobi, Kenya NBO and around $620 to Dar Es Salaam, Tanzania for travel departures from mid-January to mid-May 2020. Most tickets are bookable online through United, Lufthansa and Swiss websites. These are some of the lowest prices I recall seeing for flights to these destinations.
Tanzania has opened several high end chain hotels over the past decade for both coastal destinations around Zanzibar and inland safari/outdoor destinations around Arusha National Park and Mount Kilimanjaro.
United Airlines San Francisco SFO – Zurich ZRH – Nairobi NBO – Dar Es Salaam DAR – Zurich ZRH – SFO
United Airlines San Francisco SFO – Zurich ZRH – Nairobi NBO – Dar Es Salaam DAR- Zurich ZRH – SFO