The baths were luxurious buildings with special installations; simultaneously, they functioned as centers for recreation and social intercourse. They had at least three main rooms for bathing in cold (the frigidarium), warm (the tepidarium), and hot water (the caldarium), in addition auxiliary spaces required for their operation. The various bathing rooms had hydraulic installations, and were equipped with bathtubs. To heat the rooms, which had hot water tubs, there was a furnace (praefurnium) from which the warm air from the fire was channeled into the walls through a system of pipes and underneath the floors (hypocausts). The continuous provision of water was necessary for the baths’ operation, and was ensured by cisterns normally fed by the city’s aqueduct.
The total area covered by the baths of the complex is not known, because their excavation has not yet been completed. The building was subject to many alterations in antiquity involving changes in the use of individual spaces. The ground plan of the rooms, as this is preserved today, belongs to the final building phase.
The entrance to the baths was along the main axis linking the south entrance of the palace with the central building complex. A square vestibule with a mosaic floor led to a large rectangular reception room adorned with colored marbles on its walls and floor. There were shallow niches in the north wall, while at the east end there was a cold-water pool (frigidarium) that was later done away with, and a semi-circular decorative fountain built in its center.
Two doors in the room’s south wall led to two further areas: an octagonal one with a hexagonal warm-water bath (tepidarium), and a rectangular space with an apse on its west side, in the center of which there probably would have been a round marble basin for producing steam. In a later building phase, the apse was transformed into a bathtub. The rooms with hot water baths must have occupied the southern part of the building, which continues beneath the buildings in Navarinou Square. These rooms were heated by the furnace in an adjoining ancillary space which later changed use. The toilet (latrina) was near the entrance to the baths, south of the vestibule.
North of the room is preserved a vaulted cistern which was built later, and to its east is another building which was probably the bath’s original cistern.