CONSTITUENCY RESULT : Llanelli
| Candidate name | Party | Gender | Number of votes | Share (%) | Change vs. 2017 for party (percentage points) | ||
| Nia Griffith | Labour | Female | 16,125 | 42.2% | -11.3 | ||
| Tamara Reay | Conservative | Female | 11,455 | 30.0% | +6.3 | ||
| Mari Arthur | Plaid Cymru | Female | 7,048 | 18.4% | +0.2 | ||
| Susan Boucher | Brexit Party | Female | 3,605 | 9.4% | 0.0 |
| Election statistics | ||
| Majority | ||
| Votes | 4,670 | |
| Percent | 12.2% | |
| Rank (1 = highest %) | 466 | |
| Turnout | ||
| Constituency | 63.2% | |
| Region | 66.6% | |
| UK | 67.3% | |
| Constituency in 2017 | 67.9% | |
| Size of electorate | 60,518 | |
| Valid votes cast | 38,233 |