The Great Migration is the largest overland wildlife movement on the planet—a continuous, circular journey of more than 1.5 million wildebeest, accompanied by hundreds of thousands of zebras and gazelles, across Tanzania’s Serengeti National Park and into Kenya’s Maasai Mara National Reserve. This movement is driven by rainfall patterns, fresh grazing, and instinctive survival behavior. Unlike a one-time event, the migration unfolds year-round, shifting location each month. That’s why timing your visit is critical. Whether you want to witness dramatic river crossings, see thousands of newborn calves, or capture predator action, choosing the right month determines the quality, intensity, and cost of your safari experience.

The Mara River crossings are the most iconic and dramatic phase of the Great Migration. Between July and October, massive herds gather in the northern Serengeti, near the border with Kenya, preparing to cross the treacherous Mara River.

These crossings are unpredictable. Herds may gather for hours or even days before a single wildebeest takes the leap, triggering a chain reaction. Once the crossing begins, chaos unfolds—thousands of animals plunge into crocodile-infested waters, battling strong currents and steep riverbanks.

The Mara River itself is part of the Mara River ecosystem and is notorious for its large Nile crocodiles. These predators lie in wait, making every crossing a life-or-death event. Some animals drown, others fall prey to crocodiles, while many successfully make it across—continuing the cycle of survival.