Caerdydd Penarth

Caerdydd Penarth (Welsh for 'Cardiff [and] Penarth'; listen^ⓘ) is a proposed six-member constituency of the Senedd (Welsh Parliament; Welsh: Senedd Cymru) to be used for the 2026 Senedd election.

Caerdydd Penarth
County multi-member constituency for the Senedd
Boundary of Caerdydd Penarth in Wales
Principal areas	Cardiff Rhondda Cynon Taf Vale of Glamorgan
Preserved county	South Glamorgan
Major settlements	Cardiff (south and west), Miskin, Penarth
Future County multi-member constituency
Created	2026
Seats	6
Created from	UK Parliament boundaries: Cardiff West Cardiff South and Penarth Previous Senedd constituencies: Cardiff Central Cardiff South and Penarth Cardiff West Pontypridd Ogmore Vale of Glamorgan Previous Senedd region: South Wales Central South Wales West

It was proposed following the 2026 review of Senedd constituencies, and will be a pairing of the two UK Parliament constituencies of Cardiff West and Cardiff South and Penarth. It is to have a Welsh-only name.

Boundaries

A Senedd constituency comprising the boundaries of the UK Parliament constituencies of Cardiff West and Cardiff South and Penarth, has been proposed by the Democracy and Boundary Commission Cymru for the 2026 election to the Senedd (Welsh Parliament; Senedd Cymru). It was initially proposed using the English name Cardiff West, South and Penarth in September 2024.^[1] The pairing was then switched from Cardiff West to Cardiff East and renamed to Cardiff South-east Penarth, and its Welsh name being De-ddwyrain Caerdydd Penarth in December proposals, despite most other constituencies using Welsh-only names.^[2] It was later given the Welsh-only name Caerdydd Penarth and its boundaries were reverted back to using Cardiff West rather than Cardiff East in the commission's final recommendations in March 2025.^[3]

It encompasses parts of the principal areas (counties/county boroughs) of Cardiff, Rhondda Cynon Taf and the Vale of Glamorgan in South Wales. The constituency is to be established by 2026, following the passing of the Senedd Cymru (Members and Elections) Act 2024. The act legislates electoral reform of the Senedd to create 16 larger "super constituencies", pairing the 32 UK Parliament constituencies in Wales, and using a new fully proportional voting system, with each constituency electing six Members of the Senedd (MSs) rather than one previously.^[1]

Elections

Elections in the 2020s

Next Senedd election: Caerdydd Penarth

Party		Candidate	Votes	%	±%
	Green	Anthony Slaughter Tessa Marshall
	Plaid Cymru	Anna Brychan Kiera Marshall Leticia Gonzalez Neil Roberts Malcolm Phillips Mathew Hawkins
Majority
Turnout
Registered electors
	win (new seat)