The Serengeti versus Maasai Mara question is the one most travelers actually mean when they ask about a migration safari. These two destinations form a single continuous ecosystem straddling the Tanzania Kenya border, sharing the same wildebeest, the same Mara River, and the same Great Migration. What differs is scale, tourism development, activity rules, and which months favor which side.
Colonial era boundaries split one ecosystem into two countries with two different management philosophies. Tanzania established Serengeti National Park in 1951 and has kept tourism development deliberately restrained inside it. Kenya's Maasai Mara National Reserve followed in 1961, and grew alongside a ring of private conservancies that now offer activities the reserve itself does not. Neither approach is wrong, they simply produce different trips.
This guide is part of our broader comparison series. For the country level version of this decision, see our Tanzania vs Kenya Safari Comparison, or return to the full Safari Comparison Hub.