The Vicariate Apostolic of Wales was elevated to diocese status on 12 May 1898. The present territory of the Diocese dates from the restructuring of the Province of Cardiff by Pope John Paul II on 12 February 1987. The seat of Bishop was vacant following the retirement of Rt. Reverend Thomas Burns, S.M. in July 2019. The Diocese was overseen by the Apostolic Administrator The Most Reverend Archbishop George Stack of the Archdiocese of Cardiff. Following Stack's retirement in 2022, Pope Francis appointed Bishop Mark O’Toole as metropolitan archbishop of Cardiff and bishop of Menevia, Wales, uniting the two sees in persona Episcopi.[2]
The estimated Catholic population of the Diocese was 26,266 out of a total population of 788,550 (3.3%).
Appointed Vicar Apostolic of Wales and Titular Bishop of Ascalon on 4 July 1895 and consecrated on 14 September 1895. Appointed Bishop of Menevia on 14 May 1898 when the district was elevated to a diocese.[3]
Formerly Vicar Apostolic of Wales (1895–1898). Appointed Bishop of Menevia on 14 May 1898. Translated to the archbishopric of Cardiff on 7 March 1921.[3]
Formerly an auxiliary bishop of Menevia (1965–1972). Appointed Bishop of Menevia on 16 June 1972. Resigned on 5 February 1981 and died on 26 July 1997.[8]
Appointed Coadjutor Bishop of Menevia on 25 July 1980 and consecrated on 1 October 1980. Succeeded Bishop of Menevia on 5 February 1981. Translated to the archbishopric of Cardiff on 25 March 1983.[9]
Previously Bishop of H.M. Forces (2013–2022). Appointed Bishop of Menevia on 22 October 2008 and installed on 1 December 2008.[13] Resigned 11 July 2019.[14]
Previously Bishop of Plymouth (2004–2008). Appointed Bishop of Menevia on 22 April 2022 and installed on 23 June 2022. Also appointed Archbishop of Cardiff, thereby merging the two dioceses in persona Episcopi - in the person of the Bishop.[15]