It was Wales' only long-term, mature-student residential education college and was established in 1927 by Thomas Jones, Deputy Secretary to the Cabinet under four prime ministers including David Lloyd George and Stanley Baldwin, to continue the work of Workers' Educational Association in a residential environment, with Ben Bowen Thomas as its first warden.
Then, with Ieuan Jeffries-Jones as warden, Coleg Harlech began offering a two-year diploma course validated by the University of Wales, which became a preparation for university education for those who had missed out on earlier education: it became well known as a "second chance" college, often for people who, for economic or social reasons, never had a first chance.
In February 2017 it was announced that Coleg Harlech would be closing as an adult education site at the end of the academic year.
[2] It was sold to local businessman Leslie Banks Irvine in April 2019,[3] but then put on sale again in September that year[4] as four properties with a total asking price of around £630,000.
After it became Coleg Harlech, a library wing was added, designed by local architect Griffith Morris in an Art Deco style.
[12] Plas Wernfawr, together with the terraces revetment walls of the garden on the seaward side is a Grade II* listed building.