The1912 Carmarthen Boroughs by-election was aParliamentary by-election held in theUnited Kingdom on 24 January 1912 for theCarmarthen Boroughs constituency inWales.[1] The constituency of Carmarthen Boroughs was centred on the boroughs ofCarmarthen andLlanelli. It returned oneMember of Parliament (MP) to theHouse of Commons of theParliament of the United Kingdom, elected by thefirst past the post voting system.

The sitting Liberal MP,W. Llewelyn Williams was appointedRecorder ofSwansea, and required by the laws at the time, to seek re-election in a by-election.
The constituency had returned Liberals at every election since 1876, apart from in 1895 when a Liberal Unionist won. At the last General election in December 1910, Williams was returned unopposed. However at the previous General Election, there was a contest;
| Party | Candidate | Votes | % | ±% | |
|---|---|---|---|---|---|
| Liberal | W. Llewelyn Williams | 4,197 | 68.1 | −0.2 | |
| Liberal Unionist | Hardinge Goulburn Giffard, 2nd Earl of Halsbury | 1,965 | 31.9 | +0.2 | |
| Majority | 2,232 | 36.2 | −0.4 | ||
| Turnout | 6,162 | 91.0 | −0.2 | ||
| Registered electors | 6,772 | ||||
| Liberalhold | Swing | -0.2 | |||
Forty-five-year-old Llewelyn Williams was a local man having been born in theTowy Valley. He was educated atLlandovery College andBrasenose College,University of Oxford. He built a career in south Wales as a journalist before being called to the Bar fromLincoln's Inn in 1897. At the1906 general election, he was electedMember of Parliament (MP) forCarmarthen District. Williams held the seat at both 1910 general elections. Politically, he has opposed theBoer War, was a supporter ofDisestablishment of theChurch in Wales and a Welsh Nationalist.[3]
The Conservatives selected 48-year-old Henry Coulson Bond as their candidate. He was born in Berkshire and educated at Rugby School. Bond was a first time candidate.
The Labour Party chose F.G. Vivian to contest the seat. He had not fought an election before, and Labour had not contested this seat before.
The Liberals comfortably held the seat but with a reduced majority;
| Party | Candidate | Votes | % | ±% | |
|---|---|---|---|---|---|
| Liberal | W. Llewelyn Williams | 3,836 | 58.6 | −9.5 | |
| Conservative | Henry Coulson Bond | 2,555 | 39.1 | +7.2 | |
| Independent Labour | F G Vivian | 149 | 2.3 | N/A | |
| Majority | 1,281 | 19.5 | −16.7 | ||
| Turnout | 6,540 | 89.8 | −1.2 | ||
| Registered electors | 7,279 | ||||
| Liberalhold | Swing | -8.3 | |||
In February 1915, Williams was appointed Recorder of Cardiff and required to face another by-election, in which he was returned unopposed. Neither Bond nor Vivian stood for parliament again.