There are many places in Porto that offers a view over the city. Some of them have an entrance fee, but most of the views you get from a mirador. Here are some of the most popular places.
The Clérigos tower is one of the landmarks of Porto and is the bell tower of the Clérigos church. The church is free to enter but to enter the tower you have to pay an entrance fee.
To get the view from the tower you have to climb 230 steps of stairs. But when you’re finally up you’ll have a 360 degree view over Porto. You will see all the way to the ocean and Vila Nova de Gaia and also have a great view over the Sé Cathedral. You won’t see the famous bridge though as it is just behind the cathedral.
Outside entrance to cable car
After walking over the bridge to the south side of the city you’ll reach the entrance to the cable car that goes down to the riverside. From here you’ll have a fine view!
Mosteiro da Serra do Pilar
A short walk from The Ponte Luiz I you’ll reach the monastery where you’ll have a view over almost the entire city.
Mirador da Vitória
There are some miradors in Porto, but not even near as many as in Lisbon. This one was very close to where I was staying so I visited it more than once. The view is beautiful, but you are standing on a private lot. It would have been a perfect spot for a restaurant or café. It is open to tourists in daytime.