The ancient city of Vieux-Poitiers in the community of Naintré (Vienne) is located 3 km from the confluence of the Clain river and the Vienne river, about 25 km north-east of the city of Poitiers/Limonum (Vienne), capital of the territory of the Pictones. Although the layout of the antique city and its theatre were known for several decades, remains of its ports were only discovered recently in 2012, during an underwater survey. This bank development is located on the right bank of the Clain river, in the continuation of a road originating from the ancient city. Geophysical surveys carried out in the adjacent sector have revealed potential storage buildings, parts of which had already been identified by previous aerial surveys. The initial embankment was reinforced by an alignment of piles at the beginning of the 1st c. AD enabling access to the river. Maintenance apparently took place over several years as indicated by piles attributed to successive felling phases between 15-16 and 18-22 AD. This initial development was then replaced at the end of the 1st c. AD. by a construction of wooden caissons, filled in by a succession of backfills and connected to a pavement the use of which is still uncertain (ramp?). This more monumental construction and its maintenance can be dated to the apogee of Vieux-Poitiers. The port structure seems to have been in use until a period of decline of the antique city of Vieux-Poitiers dated to the 3rd-4th c. AD. The settlement was progressively displaced to the confluence zone at Cenon-sur-Vienne (Vienne). The site is located at the crossroads of waterways and overland roads, a strategic position for human settlement, but also a place of prime importance for trade between the Loire basin and the territory of the Pictones.