The Colligan Estuary is a tidal estuary located in County Waterford, Ireland, forming part of Dungarvan Harbour where the River Colligan broadens and enters the sea. The estuary is characterized by tidal flats and is flanked by the town of Dungarvan on one side and the area of Abbeyside on the opposite shore. A notable geographical feature is a railway causeway constructed across the estuary, which now forms part of the Waterford Greenway, a pedestrian and cycle path. This causeway and another at Barnawee were significant engineering projects due to the harsh terrain. The estuary extends inland at least as far as Ballyneety Bridge. The water body is part of the Dungarvan Harbour Special Protection Area, indicating its ecological importance. For paddlers, the primary access point is from Dungarvan Harbour itself, where the estuary meets the sea. The area is subject to tidal influence, and paddlers must be aware of the tidal currents, especially when navigating the broader harbour area before entering the more confined estuary. The presence of the causeway may influence water flow and create specific paddling conditions. The estuary is overlooked by The Park Hotel Dungarvan, which sits on its shores, and the wider area offers views of the Waterford coastline. Given its status as a protected area, paddlers should be mindful of wildlife and adhere to any regulations designed to conserve the habitat. The historical railway infrastructure, now repurposed as the Greenway, adds a cultural element to the landscape visible from the water.