Almost every highway in Portugal is a toll road and some bridges like 25 de Abril and Vasco da Gama in Lisbon have a toll.
There are normal toll roads and electronic toll roads. You need to be aware of the last ones as the payment is made electronically and if you go thru these without prior arrangement for payment there are fines evolved.
Payment methods in a normal toll
In normal tolls you can pay by debit / credit card or cash. You can choose between paying directly with a machine or with a toll both operator (with an icon of a person on top).
In these type of toll roads you grab a ticket when you enter the highway and use that ticket at your exit or when the road is no longer paid to know your point of entry and exit and the amount to pay is calculated with that information.
There is also a service called Via Verde (the white V on a green square). You cannot go thru these lanes unless you have a transponder to allow automatic debit of tolls.
If you don't have a Via Verde transponder always take the "Via Manual" (manual lane) as you will receive a fine if you go thru without a transponder
If you are driving with your own car you can rent a transponder from Via Verde. Find more information at Via Verde Visitors website.
If you are renting a car you can't have Via Verde Visitors, you need to check with your rental company if they have Via Verde to allow you to use these lanes.
Be aware that some highways have two lanes that won't have a toll both but are reserved for cars equipped with the Via Verde transponder, like on the image bellow.
If you don't have a Via Verde transponder always take the "Via Manual" (manual lane) as you will receive a fine if you go thru without a transponder.
Electronic only toll roads
There are now a few highways that were free but now are paid only electronically. They are called SCUT and have been a huge headache both for Portuguese drivers and tourists.
Unlike other tolls, in these you don't stop to pay. Either you have a transponder like Via Verde or your license plate is registered and you have 5 days to pay your tolls. However you can only do this with a Portuguese license plate.
Before entering one of these roads there is always a blue sign with a white square that has a car, some waves and a euro sign.
On each toll you are displayed with the price to pay, as seen in the picture below.
If you are renting a car in Portugal ask for one with Via Verde, if that isn't possible you need to check CTT website with the car license plate and make the payment. You have up to 5 days to do so after the date you used the toll road.
However if you are traveling with your own car, without a Portuguese license plate, you need to subscribe to EasyToll, buy a prepaid toll card or rent a Via Verde Visitors transponder.
There is a website, Portugal Tolls, created by the Portuguese government to help out with how to pay the tolls on these highways.
Car toll classes
Portuguese tolls are divided in 4 classes. Unless you are driving a truck you will only pay either class 1 or 2.
Class 1 is applied to vehicles with height measured vertically as from first axis below 1.10m, with or without trailer.
Class 2 is applied to vehicles with two axes and height measured vertically equal or above 1.10 m.
If you are driving an MPV, an SUV or a caravan you might be on the Class 2 bracket, and tolls are more expensive.
You can check the prices of tolls in this website.