Having maintained its high status as the focal point of religious and athletic celebrations for centuries, it went through several phases of major or minor destructions, reconstructions, and additions of buildings and architectural elements. The Roman baths, or thermae, are not to be confused with the original Greek baths elsewhere in the Altis. Following their own great tradition, the Romans added more baths to the existing bathing complexes.
The so-called Baths of the River Kladeos were built around 100 AD at the west end of the sanctuary, close to their namesake river and the site where the swimming pool of the Greek baths had once been. The 400-square-metre structure is connected to the nearby Roman guesthouse and consists of numerous rooms serving multiple purposes, including cold and hot pools of water, the equivalent of a modern sauna, changing rooms, bathtubs, lavatories,an atrium even a small private tub.
Contrary to what happened in the Classical and Hellenistic Era, baths in Roman times were not merely a place to bathe for hygiene or after training, but a place to socialise, relax, and enjoy the luxurious facilities and services. As it happened with most buildings bordering the banks of the Kladeos, the west part has been swept away; however, after extensive restorations in 2003, visitors are now able to visit the baths and admire the beautiful floor mosaics throughout.
Another Roman bath complex is the one near Kronios Hill, close to the sanctuary and north of the Prytaneion. Built on the former site of Hellenistic baths sometime during the Imperial Period (1-375 AD), it remained in use until the 6th century BC. The sea-related themes of the impressive floor mosaics include a Nereid on a sea bull, dolphins, and a Triton among sea horses.
After the destruction caused by an earthquake in the 3rd century BC, the building was used again after the 5th century as a ceramics workshop complete with a kiln and tanks for washing the clay, while facilities for processing agricultural goods, as well as a wine press, were also discovered.
Last but not least, the small baths located close to the Leonidaion guesthouse are one of the best-preserved buildings and also one of the few to have preserved its original roof and height. Similarly to the Kronios Baths, the floors were artfully decorated with mosaics which can still be admired today, while the building was eventually used as a wine-making facility and a glass workshop, as indicated by the kiln found among the ruins.