The hook
Tanzania's vast, wild, little-visited south, huge parks the size of small countries where you can watch wildlife along a great river with barely another vehicle in sight, the antidote to the crowded northern circuit.
01Why it's worth it
While the Serengeti and Ngorongoro draw the crowds, Tanzania's southern parks offer wilderness on an even grander and far emptier scale. Ruaha National Park, one of the largest in Africa, is a rugged land of baobabs and the seasonal Great Ruaha River, holding a large elephant population and a rich mix of predators, including big lion prides and the endangered African wild dog, where sightings feel private and hard-won. To the east, the enormous Nyerere National Park (carved from the former Selous Game Reserve) adds a different dimension: safaris here can be done by boat along the Rufiji river and its lakes, drifting past hippos, crocodiles, and elephants coming to drink, as well as by vehicle. These parks take more effort and expense to reach, usually by light aircraft, and offer fewer creature comforts than the north, but the reward is genuine wilderness and solitude for those who want their safari wild and uncrowded.
02How to experience it
Fly in to a camp in Ruaha or Nyerere for a few days of game drives, and in Nyerere add a boat safari on the Rufiji for a different perspective. Go in the dry season for the best viewing and access. Expect wilder, quieter, more exclusive safari than the northern circuit, at higher cost.
From the locals
This pin exists largely because of one line in the r/travel Tanzania thread. After running through the northern circuit — Serengeti, Ngorongoro, Manyara, Tarangire, all recommended without reservation — the same commenter added the southern parks as the real tip: "but also the southern parks of Ruaha and Selous — way way way less tourists and lots of wildlife."
Three "way"s is about as clear as an unprompted recommendation gets. The trade is the obvious one: fewer camps, longer transfers, less infrastructure, and no chance of the migration. What you get back is the thing most people actually came to Africa for and rarely describe accurately afterwards — a sighting with nobody else at it.