An election to the 58th Parliament of the United Kingdom for the constituency area of Llanelli, held as part of the general election on 12 December 2019.
Labour hold by Nia Griffith with a majority of 4,670 - 12.2% - on a turnout of 63.2%.
Candidates
| Name | Party | Vote | Vote share | Vote change |
| GRIFFITH, Nia | Lab | 16,125 | 42.2% | -11.3% |
| REAY, Tamara | Con | 11,455 | 30.0% | 6.3% |
| ARTHUR, Mari | PC | 7,048 | 18.4% | 0.2% |
| BOUCHER, Susan | BRX | 3,605 | 9.4% | - |
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 60,518, having a valid vote count of 38,233 and an invalid vote count of 152.
Result declared at 02:12 on 13 December 2019.