A new YouGov poll shows predicts that Plaid Cymru will be the largest party in Cardiff Bay after the Senedd elections in May.

The poll, conducted by YouGov for Cardiff University, has revealed that Labour’s predicted vote share for the Senedd has now fallen to 10%, while Plaid Cymru continue to lead with 33% (+3%). Reform UK’s support – at 30% – remains unchanged since the September ITV Wales YouGov poll.

The Senedd election will be held on 7 May 2026 with a new voting system, meaning people will choose a party instead of a candidate.

Plaid Cymru 33%

Reform UK 30%

Labour 10%

Conservatives 10%

Green 9%

Lib Dem 6%

Other 3%

Plaid Cymru - 39

Reform UK - 34

Labour - 10

Conservatives - 6

Green - 4

Lib Dem – 3

A Plaid Cymru spokesperson said: “Something big is truly happening in Wales.

“Coming so soon after our Caerphilly by-election win, this poll shows the momentum is firmly with Plaid Cymru and that next year’s election is shaping up to be a straight choice for Wales’ future.

“After years in power, Labour have given up on Wales. People are tired of broken promises and being taken for granted and yearning for something new: fairness, ambition, and a government that finally puts Wales first.

“At the next election, the people of Wales face two choices of two futures. One is a party rooted in Wales, focused on improving our NHS, public services, and helping families with the cost of living. The other is a billionaire-backed party that would privatise our NHS and take Wales backwards.

“This is a two-horse race, and only Plaid Cymru brings a positive vision, can stop Reform and deliver the new leadership Wales deserves.

“We’re taking nothing for granted, but if people want new leadership and a government that’s on Wales’ side, the choice is clear - get involved and vote Plaid Cymru on 7 May 2026.”

A spokesperson for Reform UK Wales said: “It’s clear to everybody here in Wales that the next Senedd Election will be a two horse race between Reform and Plaid.

“With Plaid, Wales will get more of the same extreme policies that we’ve had from Plaid and Labour working in tandem in Cardiff Bay.

“Meanwhile, Reform will be fighting to restore common sense to Welsh politics, and to deliver real change for our communities here in Wales.”

The election in May will see the number of MSs increase from the current 60 to 96.

Six members will be selected to represent each of the new 16 ‘super constituencies’, with the current 40 Senedd constituencies and five regions set to be scrapped.

Ceredigion and Pembrokeshire will be one ‘super constituency’ with another in north Wales being Gwynedd Maldwyn.

Wales will adopt a “closed-list” electoral system from 2026, with the electorate voting for political parties rather than specific candidates on the ballot paper.