Senedd constituencies

The Senedd constituencies (Welsh: etholaethau Senedd Cymru) are the electoral districts used to elect members of the Senedd (MS; Welsh: Aelodau'r Senedd or AS) to the Senedd (Welsh Parliament; Welsh: Senedd Cymru). Following reforms to the Senedd, sixteen new six-member constituencies were first contested at the 2026 Senedd election in May 2026, electing 96 members in total. The Senedd constituencies are not used for local government.

From the first election of the then National Assembly for Walesin 1999, until just prior to the 2026 Senedd election, forty single-member constituencies and five four-member electoral regions (Welsh: rhanbarthau etholiadol), electing 60 Senedd members in total, had been used. This first set of constituencies and electoral regions were created through the Government of Wales Act 1998, which established the National Assembly for Wales. The Assembly's constituencies were initially linked to the boundaries used for UK Parliament constituencies in Wales, set by the UK Parliament's Boundary Commission for Wales, except a delay in implementing new boundaries between the 2007 Assembly election and the subsequent 2010 UK election. The Parliamentary Voting System and Constituencies Act 2011, unlinked the two sets of constituencies, meaning any changes to one set, no longer affected the other.

Subsequently, the UK Parliament introduced new constituencies for its 2024 UK election, and in 2024 the Democracy and Boundary Commission Cymru was given the responsibility to conduct boundary reviews of Senedd constituencies, as there had been no designated body responsible since 2011. Following the 2026 boundary review, 16 six-member constituencies are to be used at the 2026 Senedd election, whilst the electoral regions are being abolished. The new 16 constituencies are contiguous pairings of the UK Parliament constituencies in Wales and only have Welsh names. Another review will be conducted before the 2030 election.