The Great Migration of the Serengeti is considered one of the "The Ten Wonders of the World", and one of the best events in Tanzania to witness. A truly awe-inspiring spectacle of life in an expansive eco-system ruled by rainfall and the urge for survival amongst the herbivores of the serengeti plains. Serengeti Migration. In late June and July, the migration moves into north-western Serengeti. Thus, these are the best months to see the migration in the western region of Serengeti. And, in August you can see the Great Migration in the northern Serengeti. This is when you may get to see the herds plunging into the crocodile-infested Mara River as they cross into Kenya.