A by-election was held in Hellingly on 29 October 2015 after the resignation of Conservative councillor Paul Soane, who stood in the by-election as an independent. The seat was gained by Liberal Democrats candidate David White.
A by-election was held in Crowborough East on 21 January 2016 after the death of Conservative councillor Peter Cowie.[4] The seat was won by Conservative candidate Philip Lunn.
A by-election was held in Chiddingly and East Hoathly on 20 July 2017 after the disqualification of Conservative councillor Barby Dashwood-Morris due to non-attendance.[6] The seat was won by Conservative candidate David Watts.