How Many Days Do You Need?
Most Northern Circuit trips run between four and seven days. The difference is not just length. It is how much time you spend in a vehicle versus how much time you spend watching animals.
Each park needs a different amount of time, and three things decide it: how large the park is, how far it sits from the next one, and whether you drive or fly.
Tarangire is a full day. It is close to Arusha, and the wildlife concentrates along the river, so one afternoon and one morning is enough. Most travellers sleep one night here.
Lake Manyara is a half-day to one-day trip. It is small, and the game drive circuit is short. It sits on the route between Tarangire and Ngorongoro, so it fits naturally as a stop rather than a destination. One night is plenty.
Ngorongoro Crater needs one full day and one night on the rim. The descent is best in the early morning, so you sleep nearby the night before. You do not need two nights unless you are adding a Maasai village visit or a walk along the rim.
The Serengeti is the one that changes everything. It is enormous, and the wildlife is spread across different areas depending on the season. Two nights is the minimum that makes the journey worthwhile. Three nights is better, especially between July and October when the herds are in the north.
Road or Fly-In Changes the Answer
If you are driving the whole circuit, the Serengeti needs at least two nights. The drive from Ngorongoro takes four to five hours, and you lose most of a day on the way in. One night simply does not work, because you would arrive in the afternoon and leave the next morning.
If your trip starts with a road transfer from Arusha, you cannot skip this. The distance is fixed, and the driving time has to come from somewhere.
Flying in is the only way to shorten it. A flight from Arusha to Seronera takes about 45 minutes. That turns a travel day into a game drive, which means a one- or two-night Serengeti stay becomes possible. This is the version to choose if your time in Tanzania is limited.
A Sensible Split
If you are driving: one night in Tarangire, one in Manyara, one on the Ngorongoro rim, and two or three in the Serengeti. That gives you five to seven days.
If you are flying, skip Tarangire or Manyara if time is tight; fly into the Serengeti for one or two nights, then descend into Ngorongoro on the way out. That can work in four days.
The Mistake Most People Make
One night per park sounds efficient. It is not. A single night in the Serengeti means you arrive in the afternoon and leave the next morning, and most of your time there is spent driving in and out.
The same applies to Ngorongoro. The crater descent is best in the early morning, so you need to be on the rim the night before, not arriving from three hours away.
Give the small parks one night each, and give the Serengeti two or three. If you only have four days and you are driving, drop a park rather than cutting the Serengeti short. If you want a short Serengeti stay, fly in.