St Clears (/ˈklɛərz/ KLAIRZ; Welsh: Sanclêr) is a town on the River Taf and a community in Carmarthenshire, Wales.

It is bordered by the Carmarthenshire towns and villages of Meidrim, Newchurch and Merthyr, Llangynog, Laugharne Township, Llanddowror, Eglwyscummin, Llanboidy and Llangynin.

[6] Nearby, Trefenty House became the home of a branch of the Perrot family in the 16th century, and it was here that the amateur astronomer Sir William Lower and a neighbour, John Protheroe, set up one of Britain's first telescopes in 1609, which they used to study the craters of the Moon and Halley's Comet.

[10] The building of the South Wales Railway in the 1850s was responsible for the decline of many of the small ports along the Bristol Channel coast, and St Clears was no exception.

Photographer and film-maker Stanley Phillips lived in St Clears and documented life in the town and the surrounding area (active 1910–1961).

His films include The Last March of Mr. Jonah Rees at St Clears (1930), which is in the collection of the National Library of Wales.

The permanent exhibition of Phillips' photographs and film at the Mezzanine Gallery in St. Clears[12] includes photographs of the aviator Amy Johnson, World War I flying ace Wing Commander Ira Jones, and racing drivers Sir Malcolm Campbell and J. G. Parry-Thomas, who both attempted world land speed records at nearby Pendine Sands.

[13][14] St Clears Town Hall, which is no longer used for civic purposes, is a grade II listed building.

After a local campaign to persuade the Welsh Government and Network Rail to reopen St Clears railway station,[16] funding was secured to do so by 2024.