The preservation and extensive excavations at Ostia Antica have brought to light 26 different bath complexes in the town.

The complex is also called the Thermae Gavii Maximi, named after Marcus Gavius Maximus, the praetorian prefect who sponsored their construction.

Along the southern face of the building are the warm rooms of the bathhouse, placed to take advantage of the sun's passive heating.

[19] This bath is typical of many of the balnea in Ostia, where the rooms are built into the established city grid leading to a chaotic interior layout often without a palaestra.

The bath was supplied with water by a tank equipped with a noria in the adjacent Republican Sacred Area.

[29] The building was constructed above the rubble of the collapsed insulae and reused many of the rooms in the area for the bath such as the street entrance of a former shop being converted into the apodyterium.

It has been speculated that it was the guild headquarters for the Cisiarii (Latin for Coachmen) however there is no direct evidence for this besides the subject of the mosaics.

[35] Notable is the large black-and-white mosaic in the frigidarium which depicts two sets of walls, possibly referring to Rome and Ostia, four figures of Atlas and a set of two-wheeled wagons (in Latin cisia) drawn by mules with silly names like Pudes (Prudish), Podagrosus (Gouty), Potiscus (Thirsty?

[42] The overall design of the bathhouse was similar to those found in Pompeii, such as the Central Baths and therefore represents the next aspect of development.

[43] The eponymous mosaic of Neptune riding a chariot drawn by hippocampi and surrounded by marine animals can be found after entering the bathhouse, this room is just south of the frigidarium.

The individuals in the mosaics have a three-dimensional quality to them, showing overlapping and twisting, although the scene as a whole remains flat.

[43] The Baths of Neptune are one of the few in Ostia that contains an open-air palaestra, surrounded on three sides by marble columns.

[49] There is a central exedra paved with marble that had a life-sized statue of Sabina, wife of Hadrian, dressed as the goddess Ceres.

[53][54] These remains are the earliest archaeologists have recovered of a bath complex in Osita despite epigraphic evidence suggesting some of a late Republican date.

Originally believed to be the Thermae Marittime in CIL XIV, 137 which has since been connected to the Porta Marina Baths.

[34] The bath is named after a satirical painting of seven Greek philosophers found in a room that was formerly a tavern and later used as the apodyterium,[59] the philosophers are identified by their names and city of origin written in Greek and a humorous and ironic Latin inscription referring to latrine activities.

[61][24] They were named after a mosaic found in the corridor south of the frigidarium which shows a female head with a triskeles, or three legs, behind her.

[67] The namesake mosaic can be found in the floor of the frigidarium where fish and sea monsters surround a lighthouse (pharos).

Like many of the smaller bathhouses, this one was set into the existing urban fabric with bars, shops, and apartments surrounding it.

[72] The structure has an entrance hall, frigidarium and four small heated rooms, in which black-and-white and polychrome geometric mosaics were discovered.

Faustus is shown with a victory palm, and in the small apse are a set of long jump weights and strigils and a metal oil vessel.

[73] This small bathhouse (IV, IX, 6) was a balneum built into the fabric of the house, but have only been partially excavated.

[74] A nummus of Theodosius was recovered from a secure context indicating that the bath remained in use during the first half of the 5th century C.E.

[75] The Baths of Silenus (IV, IX, 7) were discovered in 2011 as a part of the work of the Ostia Marina Project at the University of Bologna.

The 400-square meter structure was built along the ancient coastline in the extra-urban neighborhood beyond the Porta Marina Gates.

with later reuse during the Late Antique period of Ostia The name comes from the marble revetment depicting Silenus.

and then renovated several times, during the 2nd century by Publius Lucilius Gamala,[81] and in the 4th century by Proculus Gregorius,[81] and even during the reign of Theodoric based on brick stamps recovered [3] These renovations display the continued vitality of the extra-urban area of Ostia in the Late Antique/Early Medieval Period possibly due to the proximity of Portus.

[79] They were sumptuously decorated, with many statue bases found in the frigidarium and several black-and-white mosaics with athletes in various stages of the competition and holding different prizes or pieces of equipment.

[88] The Baths of the Swimmer (V, X, 3) were built during the reign of Domitian between 89-90 C.E., The structure was renovated during the city-wide improvements under Hadrian and Antoninus Pius, which modifications occurring in between 180-200 C.E.

[94] Outside the traditional regions of Ostia, a small Late Antique bathhouse came to light during soundings done by the German Archaeological Institute in Rome.