Isle of Anglesey County Council, Ynys Gybi – 5 February 2026
No Lib Dem candidate
Pembrokeshire Council, Fishguard North East – 10 February 2026
Labour seat (subsequently Independent). Cause: Death. Liberal Democrat candidate: Caleb Churchill
Caerphilly CBC, Van – 19 February 2026
Labour seat. Cause: Death. Liberal Democrat candidate: Tony Potts.
N.B. Please note that during the Senedd election campaign regulated period, the by election agent will need to liaise with the local party treasurer on any expenditure partial apportioned to the party.