On the 11th of March 2025, the Democracy and Boundary Commission Cymru submitted to Welsh Ministers its “Final Determinations” for the new Senedd Constituencies. With the process now finalised, the decisions will take effect automatically at the 2026 Senedd elections.

After the introduction of the Senedd (Members and Elections) Act 2024, the Democracy and Boundary Commission Cymru was made responsible for deciding on and implementing constituency boundary and name changes in Wales ahead of the 2026 election. The organisation was to account for the following criteria:

• 16 constituencies are to be created which combine the 32 UK Parliamentary constituencies. 
• Local ties, special geographical considerations and local government boundaries are to be considered. 
• A single name and designation for each proposed constituency must be created and presented. 

Initial proposals were made by the Commission in September 2024. This was followed by a consultation process. After receiving over 3,741 representations, revised proposals were made public in December. Afterwards, members of the public, groups and organisations were invited to submit representations during a second consultation. 

Taking into consideration the provisions set out by the Act and the representations of the second consultation, the Commission decided on the following final constituency boundaries and names: 

• Bangor Aberconwy and Ynys Môn UK Parliamentary constituencies to become Bangor Conwy Môn.
• Clwyd East and Clwyd North UK Parliamentary constituencies to become Clwyd.
• Alyn and Deeside and Wrexham UK Parliamentary constituencies to become Fflint Wrecsam.
• Dwyfor Meirionnydd and Montgomeryshire and Glyndŵr UK Parliamentary constituencies to become Gwynedd Maldyn .
• Ceredigion Preseli and Mid and South Pembrokeshire UK Parliamentary constituencies to become Ceredigion Penfro.
• Caerfyrddin and Llanelli UK Parliamentary constituencies to become Sir Gaerfyrddin 
• Gower and Swansea West UK Parliamentary constituencies to become Gŵyr Abertawe
• Brecon, Radnor and Cwm Tawe and Neath and Swansea East UK Parliamentary constituencies to become Brycheiniog Tawe Nedd.
• Aberafan Maesteg and Rhondda Ogmore UK Parliamentary constituencies to become Afan Ogwr Rhondda. 
• Merthyr Tydfil and Pontypridd UK Parliamentary constituencies to become Pontypridd Cynon Merthyr 
• Blaenau Gwent and Caerphilly UK Parliamentary constituencies to become Blaenau Gwent Caerffili Rhymni.
• Monmouthshire and Torfaen UK Parliamentary constituencies to become Sir Fynwy Torfaen.
• Newport East and Newport West and Islwyn UK Parliamentary constituencies to become Casnewydd Islwyn.
• Cardiff West and Cardiff South UK Parliamentary constituencies to become Caerdydd Penarth.
• Cardiff North and Cardiff East UK Parliamentary constituencies to becomeCaerdydd Ffynnon Taf.
• Bridgend and Vale of Glamorgan UK Parliamentary constituencies to become Pen-y-bont Bro Morgannwg.

Through its final proposals, the Democracy and Boundary Commission Cymru has decided that all constituencies are to have a Welsh-only name, with no constituencies having an alternative English name. Additionally, six members of the Senedd will be elected per constituency. 

The areas which saw most changes throughout the consultation process were in Cardiff. After pairing Cardiff North with Cardiff West and Cardiff East with Cardiff South and Penarth in the December proposals, the Commission has reverted back to its initial plans from September. Cardiff North and Cardiff East will be paired to form Caerdydd Ffynnon Taf and Cardiff West and Cariff South and Penarth will be paired to form Caerdydd Penarth. 

In justification of the final decisions, Beverley Smith, Chair of the Democracy and Boundary Commission Cymru, stated that the Commission looked carefully at the 365 representations made in December and January. However, they had to balance the issues raised in representations against all other factors and constraints from legislation. 

What happens next?

After having made a decision on the new constituency boundaries and names, the Commission is to present its report before the Senedd. Although this does not need approval and will be adopted automatically, the Welsh Government is to make secondary legislation to bring the Commission’s decisions into law. 

In 2026, a new future for the Senedd is to be drawn as the reform introduced important questions on political shifts in Wales. Through constituency, member and electoral changes the new Senedd will most likely look more diverse, with a proportional system set to increase representation for smaller parties. This is not only the case for Reform, but also the Liberal Democrats, the Greens, and Plaid Cymru. 

News of the so-called “threat of Reform” to bigger parties such as Labour signifies greater political changes. Among the regions where Reform UK could likely gain ground are the Labour-voting heartlands of south Wales valleys and part of rural mid Wales. Carwyn Jones, member of the House of Lords and former Leader of Welsh Labour, urges his former party to reclaim its title as the party of working people.