The Senedd constituencies () are the electoral districts used to elect members of the Senedd (MS; ) to the Senedd (Welsh Parliament; ). 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 Wales in 1999, until just prior to the 2026 Senedd election, forty single-member constituencies and five four-member electoral regions (), 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.
Current constituencies (from 2026)
The following is the list of current constituencies, in use from the 2026 Senedd election, and their current members.
Constituency CountyCurrent members Population (2024) Map Afan Ogwr RhonddaGlamorganSteve Bayliss (Reform)Alun Cox (Plaid Cymru)Sera Evans (Plaid Cymru)Huw Irranca-Davies (Labour)Benjamin McKenna (Reform)Elyn Stephens (Plaid Cymru)194,083Bangor Conwy MônClwyd, GwyneddRhun ap Iorwerth (Plaid Cymru)John Clark (Reform)Janet Finch-Saunders (Conservative)Helen Jenner (Reform)Mair Rowlands (Plaid Cymru)Elfed Williams (Plaid Cymru)163,460Blaenau Gwent Caerffili RhymniGlamorgan, GwentCatherine Cullen (Reform)Delyth Jewell (Plaid Cymru)Joshua Kim (Reform)Niamh Salkeld (Plaid Cymru)Llŷr Powell (Reform)Lindsay Whittle (Plaid Cymru)192,579Brycheiniog Tawe NeddGlamorgan, PowysJane Dodds (Liberal Democrat)James Evans (Reform)Iain McIntosh (Reform)David Mills (Reform)Rebeca Phillips (Plaid Cymru)Sioned Williams (Plaid Cymru)194,514Caerdydd Ffynnon TafGlamorganZaynub Akbar (Plaid Cymru)Nick Carter (Plaid Cymru)Cai Parry-Jones (Reform)Paul Rock (Green)Shav Taj (Labour)Dafydd Trystan (Plaid Cymru)212,885Caerdydd PenarthGlamorganAnna Brychan (Plaid Cymru)Leticia Gonzalez (Plaid Cymru)Kiera Marshall (Plaid Cymru)Joe Martin (Reform)Anthony Slaughter (Green)Huw Thomas (Labour)220,137Casnewydd IslwynGwentLyn Ackerman (Plaid Cymru)Natasha Asghar (Conservative)Jayne Bryant (Labour)Peredur Owen Griffiths (Plaid Cymru)Dan Thomas (Reform)Art Wright (Reform)220,058Ceredigion PenfroDyfedClaire Archibald (Reform)Paul Davies (Conservative)Kerry Ferguson (Plaid Cymru)Elin Jones (Plaid Cymru)Paul Marr (Reform)Anna Nicholl (Plaid Cymru)198,360ClwydClwydLouise Emery (Reform)Llyr Gruffydd (Plaid Cymru)Becca Martin (Plaid Cymru)Adrian Mason (Reform)Darren Millar (Conservative)Thomas Montgomery (Reform)198,297Fflint WrecsamClwydCristiana Emsley (Reform)Carrie Harper (Plaid Cymru)Marc Jones (Plaid Cymru)Sam Rowlands (Conservative)Ken Skates (Labour)Nigel Williams (Reform)204,672Gwynedd MaldwynGwynedd, Powys, ClwydMabon ap Gwynfor (Plaid Cymru)Beca Brown (Plaid Cymru)Andrew Griffin (Reform)Siân Gwenllian (Plaid Cymru)Claire Johnson-Wood (Reform)Elwyn Vaughan (Plaid Cymru)195,838Gŵyr AbertaweGlamorganJohn Davies (Plaid Cymru)Safa Elhassan (Plaid Cymru)Mike Hedges (Labour)Francesca O'Brien (Reform)Steven Rodaway (Reform)Gwyn Williams (Plaid Cymru)211,891Pen-y-bont Bro MorgannwgGlamorganSarah Cooper-Lesadd (Reform)Andrew RT Davies (Conservative)Mark Hooper (Plaid Cymru)Sarah Murphy (Labour)Sarah Rees (Plaid Cymru)Gaz Thomas (Reform)194,600Pontypridd Cynon MerthyrGlamorganSara Crowley (Plaid Cymru)Heledd Fychan (Plaid Cymru)Vikki Howells (Labour)David Hughes (Reform)Lis McLean (Plaid Cymru)Jason O'Connell (Reform)205,358Sir Fynwy TorfaenGwentDonna Cushing (Plaid Cymru)Peter Fox (Conservative)Matthew Jones (Plaid Cymru)Laura Anne Jones (Reform)Lynne Neagle (Labour)Stephen Senior (Reform)189,049Sir GaerfyrddinDyfedGareth Beer (Reform)Cefin Campbell (Plaid Cymru)Carmelo Colasanto (Reform)Sarah Edwards (Reform)Nerys Evans (Plaid Cymru)Adam Price (Plaid Cymru)190,800
History
Establishment Following the 1997 Welsh devolution referendum, where a narrow majority voted in support of the creation of a devolved Welsh Assembly, constituencies of the devolved legislature were established.
Section 2 of the Government of Wales Act 1998 stipulates that the constituencies for the National Assembly for Wales be the same as the constituencies used for elections to the United Kingdom Parliament. The same act sets out the creation of five regions which would use the same borders as the five European Parliamentary constituencies in Wales which themselves were set out in the European Parliamentary Constituencies (Wales) Order 1994, used for elections to the European Parliament between 1994 and 1999. The electoral regions set out are still used, despite the abolishment of the five European Parliamentary constituencies for an all-Wales constituency, and the withdrawal of the UK from the European Union. Although minor border adjustments to the regions have taken place.
2007 change in boundaries In 2006, the Government of Wales Act 2006 was enacted. When enacted the act reinforced the link between Assembly and UK Parliamentary constituencies, and that the number of electoral regions is five.
Following the fifth periodic review of Westminster constituencies, new borders for the constituencies and electoral regions were defined by the Parliamentary Constituencies and Assembly Electoral Regions (Wales) Order 2006.
The order detailed the abolition of three constituencies (Caernarfon, Conwy, and Meironnydd Nant Conwy), with three new constituencies to replace them (Aberconwy, Arfon, and Dwyfor Meirionnydd). Nine constituencies were subject to "substantial" border adjustments involving the transfer of more than 3,000 inhabitants between constituencies. A further eight constituencies were subject to boundary changes resulting in the redistribution of fewer than 3,000 inhabitants between each constituency, and a further four constituencies were subject to minor boundary adjustments that led to minimal transfers of inhabitants between constituencies. The remaining sixteen constituencies were not subject to any boundary or name modifications.
The three new constituencies straddled the border of the electoral regions of Mid and West Wales and North Wales, leading to adjustments in the boundaries of both electoral regions, in addition to minor adjustments to the constituency of Montgomeryshire also leading to minor regional boundary adjustments. In south Wales, the boundaries of the electoral regions, South Wales West, and South Wales Central were altered to accommodate changes to the boundaries of Bridgend, and Vale of Glamorgan constituencies.
The changes in the boundaries for constituencies and electoral regions of the Senedd came into force for the 2007 National Assembly for Wales election.
Delinking from UK parliament constituencies Section 13(1) of the Parliamentary Voting System and Constituencies Act 2011 states that:
This details that any further changes to the UK Parliament constituencies in Wales specified in the act (notably the proposed reduction in constituencies to 30) will not be applied to Assembly (Senedd) constituencies.
In a session of the House of Commons where the then secretary of state for Wales, Cheryl Gillan was questioned on the Labour party's opposition to the decoupling of the two constituencies, she replied:
Boundaries of Senedd constituencies and electoral regions were initially not overseen by any statutory review body, following the delinking of Senedd and UK Parliament constituencies in 2011. With the responsibility for proposing alterations to the boundaries of UK Parliament constituencies in Wales, and reporting to the UK Government, lay with the Boundary Commission for Wales. At the time, both constituencies had the same boundaries. Organisations such as the Electoral Reform Society Cymru indicated a preference for coterminosity (mirroring Senedd and UK Parliament constituencies, especially during the 2016 proposed reforms). However, such coterminosity was merely desired and was not enforced by law, meaning any changes to UK Parliament constituencies in Wales did not need to be mirrored for Senedd constituencies. The 2023 review of Westminster constituencies reduced the number of UK Parliament constituencies in Wales from 40 to 32, and were used from the 2024 UK election. While the Senedd is to introduce larger constituencies composed of pairings of the 32 from 2026.
2020 renaming On 6 May 2020, the Senedd and Elections (Wales) Act 2020 came into force, renaming the Assembly constituencies and Assembly electoral regions of the National Assembly for Wales, to the Senedd constituencies and Senedd electoral regions of "Senedd Cymru" or "the Welsh Parliament", known in both Welsh and English as the Senedd.
2024–25 boundary review
The Senedd Cymru (Members and Elections) Act 2024, passed by the Senedd in May 2024, gave the responsibility for conducting boundary reviews of Senedd constituencies to the Democracy and Boundary Commission Cymru. The commission would be responsible to conduct reviews for specifically both the 2026 Senedd election and the 2030 Senedd election, as well as regular reviews thereafter. The 2026 review was time-constricted, therefore the 2030 review, the first full boundary review in 18 years, would provide the commission with more flexibility.
The Senedd Cymru (Members and Elections) Act 2024 legislated that the 2026 election should use 16 six-member constituencies, replacing the existing 40 constituencies and five regions, with the Democracy and Boundary Commission Cymru conducting the review. The law set out that they must be contiguous pairings of the 32 UK Parliament constituencies used in Wales since 2024, and to only use a single name in both Welsh and English, unless it could be considered unacceptable for a single name. The review commenced in July 2024, with initial proposals revealed in September 2024, and revised proposals in December 2024. A major change in the revised proposals was the use of mostly Welsh-language names only to meet the condition in law, therefore all (except four) had only one name, its Welsh name. The decision received support from Cymdeithas yr Iaith, but opposition from Andrew RT Davies, former leader of the Welsh Conservatives. In March 2025, the commission published its final determinations, for the 16 constituencies (see ). The original initial proposal boundaries were re-adopted, while all constituencies were made to use Welsh-only names, with a reiteration of both support and opposition from Cymdeithas and Davies respectively, as well as consultation respondents. By law, the Senedd must put these final determinations into effect for the 2026 Senedd election without alteration.
2030 boundary review