Welney is a village and civil parish in the Fens of England, and the county of Norfolk. The village is situated immediately to the west of parallel Old Bedford River, River Delph and New Bedford River, which are here crossed by the A1101 road. The village is some south-west of the town of Downham Market, south of the town of King's Lynn and west of the city of Norwich. The county boundary with Cambridgeshire is adjacent, and the city of Cambridge lies to the south.
Welney is situated on the Ouse Washes, an internationally important area of wildlife conservation. WWT Welney is a nature reserve in the care of the Wildfowl and Wetlands Trust. Nearby, there are also the RSPB Ouse Washes, a reserve managed by the Royal Society for the Protection of Birds.