Wales holds its first election to a 96-seat Senedd on 7 May 2026 under a new closed-list proportional representation system. The chamber expands from 60 seats to 96 across 16 six-member constituencies, with seats allocated by the D'Hondt method. Each party publishes a ranked list of up to eight candidates per constituency; voters cast a single vote for a party, not a candidate, and seats are awarded to list positions in order until the constituency's six seats are filled.
The system replaces the previous Additional Member System (AMS) that had been used at every Senedd election since the chamber opened in 1999. The Senedd Research Service estimates a party needs roughly 12 per cent of a constituency vote to win a single seat, the implicit threshold the D'Hondt arithmetic produces across a six-member district. Any party falling below that line in a constituency takes no seat there regardless of its national share.
The change is the largest single reform to the Welsh electoral system since devolution began. Voters who previously cast a constituency vote and a regional list vote now cast only one, for a party. The identity of the person who reaches Cardiff Bay depends entirely on how each party has ordered its internal list, a decision taken inside party machinery before nominations. The 96-seat expansion is paired with no statutory gender floor, following the withdrawal of the Senedd Cymru (Electoral Candidate Lists) Bill in September 2024, leaving women's representation dependent on internal party list-ordering decisions.
