The so-called Kronios, or north baths, lie to the north of the Prytaneion, near the foot of Kronios hill. The building was raised in Imperial times over a Hellenistic building and baths, was remodeled several times since and remained in use until the fifth to sixth centuries AD. A small bath complex was added to its north-east side during this last period.
This complex comprised a central peristyle court surrounded by many rooms. The court had a beautiful mosaic floor with marine themes. A Nereid mounting a sea-bull was depicted on the central panel of the south side and a dolphin on the central panel of the north side. On the west side, where the main entrance was, a Triton among sea-horses was portrayed. The building suffered from an earthquake in the third century AD, and was subsequently re-used for agricultural and manufacturing activities in the fifth and sixth centuries. A wine press occupied the east section of the court, and several rooms to the north and east housed a pottery workshop. A pottery kiln was later built inside the apsed tepidarium. Three tanks situated in the north wing of the complex were probably connected with pottery manufacture and were used for the washing and preparation of clay. A large number of vases and pottery sherds date the workshop to the fifth and sixth centuries AD.
The building was revealed at the end of the first German excavation campaign in 1880, and was almost fully investigated in the years 1987-1991. Further study of the earlier building phases was conducted in 2003, together with conservation of the mosaics. The court mosaic was restored to its original position, while another floor mosaic from the north rooms is displayed in the Olympia Archaeological Museum.