An election to the 58th Parliament of the United Kingdom for the constituency area of Carmarthen West and South Pembrokeshire, held as part of the general election on 12 December 2019.
Conservative hold by Simon Hart with a majority of 7,745 - 18.4% - on a turnout of 71.2%.
Candidates
| Name | Party | Vote | Vote share | Vote change |
| HART, Simon | Con | 22,183 | 52.7% | 5.9% |
| TIERNEY, Marc | Lab | 14,438 | 34.3% | -5.2% |
| THOMAS, Glanville | PC | 3,633 | 8.6% | -0.7% |
| CAMERON, Alistair | LD | 1,860 | 4.4% | 2.2% |
Under section 13(b) of the Representation of the People Act 1985, a candidate gaining 5% or less of the vote share will forfeit their deposit.
An electorate of 59,158, having a valid vote count of 42,114 and an invalid vote count of 146.
Result declared at 04:21 on 13 December 2019.