The Serengeti's name means "endless plains" for good reason -- this is where most of the Great Migration actually happens, alongside Ngorongoro Crater's dense, self-contained wildlife bowl. Tanzania's real advantage is what comes after the safari: Zanzibar's beaches sit close enough to fold into the same trip, so a Northern Circuit safari and a week on the coast can sit on one itinerary rather than two separate holidays.
The Serengeti's migration timing shifts through the year -- calving season in the southern plains typically falls January to March, river crossings further north roughly June to September. Zanzibar's driest, sunniest stretch generally runs June to October, which is also when most travellers combine both legs of the trip.
A sample of Tanzania's lodges and camps, across three tiers
Full Board
Half Board
Half Board
All-Inclusive
Illustrative starting points: every trip is built around you.
5 nights: Serengeti & Ngorongoro
8 nights: Northern Circuit & Zanzibar
10 nights: Tanzania in Full