Member of the Senedd


is composed of sixty members known as Members of the Senedd or MSs. Forty are chosen to represent an individual Senedd constituency, and twenty are chosen to represent the five electoral regions in Wales.
Each person in Wales is represented by five MSs: one for their constituency, and another four covering their region. Wales's five electoral regions are Mid and West Wales, North Wales, South Wales Central, South Wales East and South Wales West.
Prior to May 2020, holders of this office were Assembly Members or AMs.

Methods of election

MSs are elected in one of two ways:
  1. First-past-the-post constituency or
  2. Regional additional-member
Forty are elected as constituency MSs and twenty are elected as additional members, four from each of five regional groups of constituencies. This additional member system produces a form of proportional representation for each region.

Elections

All MSs positions become simultaneously vacant for elections held on a four-year cycle. If a vacancy arises at another time, due to death or resignation, it may be filled in one of two ways, depending on whether the vacancy is for a first-past-the-post constituency MS or for an additional-member MS.
A constituency vacancy may be filled by a by-election. An additional-member vacancy may be filled by the next available candidate on the relevant party list.