Protonuraghe Protonuraghes are considered to be the most archaic type; they differ somewhat from the "classical" (tholos-vaulted) nuraghes in their stockier look. Protonuraghes generally follow an irregular plan and lack the large circular room present in presumed later forms; instead, they are laid out along one or more corridors or long rooms. Although lacking the central circular room, they are sometimes similar in size to later nuraghes.
Mixed nuraghe This type is distinguished by the restorations made in later times, supposedly because of a change to the protonuraghes design, or for other needs.
Single-tower nuraghe This is considered to be the predominant type of nuraghe, and it represents the most diffused typology. The single tower, of a truncated conical shape, contains one or more superimposed chambers, covered by a
tholos-shaped chamber. The access, generally located at the ground level, leads into a passageway that leads, in the front, into the central chamber and in one side (usually the left) in the helical staircase, built inside the wall mass, that lead to the terrace or to the upper-floor chamber. In addition to the usual circular rooms, in their inside can be found other smaller environments such as niches.
A "tancadu" nuraghe A "tancadu" nuraghe (
Sardinian term for courtyard) represents the evolution of the single-tower nuraghe; another circular building was later added to the main tower, with two enclosing curtain walls connecting the two. A courtyard was present within the structure, sometimes provided with a well.
Polylobed nuraghe Also called
Nuragic royal palaces, the polylobed nuraghes are the least frequent typology. Very elaborate and often designed in a unified manner, they look like veritable fortresses with several towers linked by high ramparts, whose function was to offer more useful space and perhaps to reinforce the central tower. These "Megalithic castles" were surrounded by additional walls, sometimes also provided with towers (the so-called bulwark). ==Notable nuraghes==