From late September to end of October you can get to see the reverse migration as the wildebeest head from Masai Mara to the Serengeti.
The migration route is sometimes thought of as a set circuit that occurs between Tanzania's Serengeti plains in the south and Kenya's Maasai Mara in the north. But that isn’t exactly the whole story. Don’t let orderly maps claiming to predict the pathways fool you. Since this is a completely natural process that depends on weather, environmental factors, and the animals themselves, the timing and route that’s well-known—from the southern Serengeti through the Western Corridor up to the Maasai Mara then back to the start through the Loliondo and Lobo area—is more of an estimation than a reliable roadmap.