The report from the Williams Commission proposes the following council mergers:
- Anglesey and Gwynedd
- Conwy and Denbighshire
- Flintshire and Wrexham
- Ceredigion and Pembrokeshire
- Neath Port Talbot and Bridgend
- Rhondda Cynon Taf and Merthyr Tydfil
- Cardiff and the Vale of Glamorgan
- Blaenau Gwent, Caerphilly and Torfaen
- Monmouthshire and Newport
If Carmarthenshire, Powys and Swansea are left unchanged, there would be 12 local authorities. The Commission says this "represents the minimum viable level of change".
It suggests that Swansea could join the combined Neath Port Talbot and Bridgend, with Carmarthenshire joining Ceredigion and Pembrokeshire.