Senedd Elections 2026 – the remaking of Welsh politics?

The 2026 Senedd election is set to be one of the most consequential in Welsh history with the Senedd set to see major changes, driven in equal parts by a new system and a changing political landscape.

This blog post was written by Matthew Ball, an Economics and Politics student at the University of Exeter.

A bigger Senedd, a new Senedd

The 2026 election is the first that will be held under a new electoral system in Wales. The Elections and Elected Bodies (Wales) Act 2024 introduced reforms to the electoral system designed to modernise the Senedd and reduce the number of wasted votes. The most significant change is increasing the size of the Senedd from its current size of 60 members to 96 members, after the May 2026 election.

The way in which this expanded cohort of MS’s are elected is also changing. Wales will now have 16 constituencies, with each constituency electing 6 members through a closed proportional list method. Voters will have the opportunity to vote not for a candidate, but for a party, with the D’Hondt method being used to divide the seats fairly between parties based on their share of the vote.

With the aim of this system being to improve proportionality and decrease the number of wasted votes, it provides opportunities to historically smaller parties like the Greens or independents to capture seats in the Senedd.

Polls point to Coalition Politics

The electoral changes come into effect at a tumultuous time in Welsh politics, with a Reform upsurge coinciding with voters’ dissatisfaction with the Labour governments in both Westminster and Cardiff Bay.

The most recent polls have Plaid Cymru, Reform and Labour interchangeable as the leading parties, with them all polling between 20 and 30%, whilst the Conservatives are on track to lose a significant number of seats, with latest projections having them on course to capture just 13% of the vote share.

Under the new proportional representation method, recent polling has no party coming close to an overall majority (49 seats), with current projections suggesting the biggest party may gain only 35 seats. It is worth noting that this is to be expected, with an overall majority under proportional representation systems being exceedingly rare – the SNP managed it once in 2011 by a razor thin margin – with a vote share of over 45%. With an overall majority all but off the cards, the Senedd is almost certainly set for another coalition or power sharing agreement in 2026. The most likely coalition or cooperative partnership will be Labour and Plaid Cymru, who between them may be able to generate well over the 49 seats needed. This agreement will likely look different to those seen in previous years as it will have Plaid play a much larger role, perhaps as the lead partner if Labour’s polling performance doesn’t improve.

The likely necessity for a coalition may leave Reform in an isolated position. Despite some polls having Reform on track to becoming the largest party in Wales, if they cannot find coalition partners, they may be unable to form a government – which will create animosities of its own for the party faithful. The Conservative party are the most likely partner in any power sharing agreement, but with the Conservatives currently denouncing any cooperation agreements with Reform, the Senedd’s post-election coalition negotiations could become a hotly debated topic in national political discourse with implications for the next general election too. 

Prepare for the unpredictable

As the next Senedd is likely to be more diverse and multiparty-driven, what does this mean for public affairs professionals? Firstly, the new system of constituency MS’s makes advocacy work immediately more complex. Gone are the days of lobbying a single member for an issue in their constituency, instead campaigners will have to attempt to harbour support from multiple members, often from different parties with different political priorities, on each issue. This will require more in-depth stakeholder mapping and a wider range of contacts, which makes specialist public affairs support all the more vital.

Furthermore, due to the more evenly balanced – and larger – Senedd, there will be a number of new Senedd Members in May 2026. For those seeking to influence MS’s, this shift creates an opportunity to identify candidates in winnable seats and begin engaging with them early. Building the foundations of a relationship now and sharing your key messages ensures you are recognised and that your priorities are carried into the coalition negotiations after the election.

It may still be too soon to know the details of what the Senedd will look like in 2026, but organisations and businesses would be wise to prepare for any possible scenario in what is rapidly shaping up to be the most unpredictable election since the beginning of Welsh devolution.