2026 review of Senedd constituencies
The 2026 review of Senedd constituencies was conducted between July 2024 and March 2025 by the Democracy and Boundary Commission Cymru. The Senedd Cymru (Members and Elections) Act 2024 legislated that the 2026 Senedd election should use 16 six-member constituencies under a party-list proportional representation system, replacing the existing 40 constituencies and five regions currently used for the Senedd. The constituencies are required by the law to be contiguous pairings of the 32 UK Parliament constituencies used in Wales since the 2024 UK election. The commission were also required by the law to give constituencies a single name in both Welsh and English, unless it could be considered unacceptable for a single name. However, the commission eventually announced they are to all exclusively use Welsh.
Background
The Senedd Cymru Act 2024, also nicknamed the "Senedd Reform Act", was introduced to the Senedd on 18 September 2023, and received royal assent on 24 June 2024. It was the culmination of various proposals for reforming the Senedd, particularly the increase in the numbers of members of the Senedd, and changing the existing voting system.As part of the [2021 Welsh language|Welsh Labour–Plaid Cymru agreement|2021 co-operation agreement] between Welsh Labour and Plaid Cymru, the parties agreed on an expansion of the Senedd to between 80 and 100 Members and a more proportional voting method. Leaders of the two parties announced in a May 2022 joint position statement calling for a 96-Member Senedd, all elected through closed party list proportional representation, as well as "zipping" of male and female candidates, so at least 50% of those on lists are women, but the zipping proposal was later postponed in 2023.
The 2024 act renamed the Local Democracy and Boundary Commission for Wales to the "Democracy and Boundary Commission Cymru", and gave it the responsibility to conduct boundary reviews of the Senedd constituencies for both the 2026 and 2030 Senedd elections, and regular boundary reviews thereafter.
Following the reduction in the number of Welsh MPs and the implementation of new constituency boundaries for the 2024 UK general election, the proposals and subsequently the 2024 act, required the new Senedd constituencies to be contiguous pairings of the 32 UK Parliament constituencies used in Wales since the 2024 UK election. Therefore there would be 16 constituencies, electing six members each, to replace the existing 40 constituencies and five regions. The commission was also required by the law to give constituencies a single name in both Welsh and English, unless it could be considered unacceptable for a single name. The commission later decided all the new constituencies were to use Welsh-only names.
The review began in July 2024. The 2026 review was time-constricted, therefore the subsequent 2030 review, the first full boundary review in 18 years, would provide the commission with more flexibility.
Initial proposals (September 2024)
The Democracy and Boundary Commission Cymru revealed its initial proposals for the proposed new constituencies in September 2024, following the commencement of the review in July 2024.Revised proposals (December 2024)
In December 2024, the commission published its revised proposals following a consultation. The two major changes were the switching of the Cardiff constituencies into different pairs, and the announcement that all of the constituencies will have Welsh-language names only, not having English-language names.The decision for only Welsh-language names received support from Cymdeithas yr Iaith, but the society called for the remaining four English names to be removed as well. They further suggested cutting the compass directions from the excepted names if needed for them to be Welsh-only. While Andrew RT Davies, former leader of the Welsh Conservatives, called the decision a "disenfranchise" of English-language only speakers, and called for constituencies covering English-speaking majority areas to have English-language names as well. The commission was required by law to give constituencies a single name for use in both languages, unless it was considered unacceptable. With four constituencies having bilingual names in the revised proposals.
| Revised proposed Senedd constituency | UK Parliament constituencies |
| Afan Ogwr Rhondda | Aberafan Maesteg |
| Afan Ogwr Rhondda | Rhondda and Ogmore |
| Bangor Conwy Môn | Bangor Aberconwy |
| Bangor Conwy Môn | Ynys Môn |
| Blaenau Gwent Caerffili Rhymni | Blaenau Gwent and Rhymney |
| Blaenau Gwent Caerffili Rhymni | Caerphilly |
| Gogledd-orllewin Caerdydd | Cardiff North |
| Gogledd-orllewin Caerdydd | Cardiff West |
| De-ddwyrain Caerdydd Penarth | Cardiff East |
| De-ddwyrain Caerdydd Penarth | Cardiff South and Penarth |
| Casnewydd Islwyn | Newport East |
| Casnewydd Islwyn | Newport West and Islwyn |
| Ceredigion Penfro | Ceredigion Preseli |
| Ceredigion Penfro | Mid and South Pembrokeshire |
| Clwyd | Clwyd East |
| Clwyd | Clwyd North |
| Fflint Wrecsam | Alyn and Deeside |
| Fflint Wrecsam | Wrexham |
| Gwynedd Maldwyn | Dwyfor Meirionnydd |
| Gwynedd Maldwyn | Montgomeryshire and Glyndŵr |
| Sir Gâr | Caerfyrddin |
| Sir Gâr | Llanelli |
| De Powys Tawe Nedd | Brecon, Radnor and Cwm Tawe |
| De Powys Tawe Nedd | Neath and Swansea East |
| Gorllewin Abertawe Gŵyr | Swansea West |
| Gorllewin Abertawe Gŵyr | Gower |
| Merthyr Cynon Taf | Merthyr Tydfil and Aberdare |
| Merthyr Cynon Taf | Pontypridd |
| Mynwy Torfaen | Monmouthshire |
| Mynwy Torfaen | Torfaen |
| Pen-y-bont Bro Morgannwg | Vale of Glamorgan |
| Pen-y-bont Bro Morgannwg | Bridgend |
Final proposals (March 2025)
In March 2025, the commission published its final determinations, for the 16 constituencies, with the only change in boundaries being to revert the two Cardiff constituencies back to the pairing of the initial proposals, Cardiff North–Cardiff East and Cardiff West–Cardiff South and Penarth, creating Caerdydd Ffynnon Taf and Caerdydd Penarth respectively.By law, the Senedd must put these final determinations into effect for the 2026 Senedd election without alteration. The commission is to conduct another full boundary review of Senedd constituencies following the 2026 election and the first in 18 years, for the subsequent Senedd election scheduled for 2030.
Welsh-only names
In the final proposals, several constituency names were changed, giving all of them a single Welsh-only name, including the remaining four which had been bilingual in the revised proposals. This met the conditions set in law that the constituencies must have a single name for use in Welsh and English, unless it was considered unacceptable.The use of all Welsh-only names prompted a re-iteration of support from Cymdeithas yr Iaith chairman Joseff Gnagbo, who stated the move to be an "important precedent" for any future constituencies to also have Welsh-only names and for Welsh-only names to be used in other contexts as well. While the move received condemnation from former Welsh Conservative leader Andrew RT Davies stating that respondents to the commission's consultation mentioned that it "disenfranchised them", commenting that "they were ignored", and that "Wales is bilingual and constituency names should be in both languages". Other Conservative MSs from Powys claimed the larger constituencies means the link between representatives and constituents "will be lost" and criticised the loss of "Radnorshire" from the map.
The commission stated the Welsh-only names were "acceptable and recognisable for people across Wales". Shreen Williams, the head of the commission, stated that the move prompted a "pushback", but backed it stating that the opposition they received was "primarily anti-Welsh sentiment", which was "incredibly disappointing". The final consultation had over 4,000 responses and was described by the commission to have received more responses then any other consultation "by a considerable margin".