In 1850, Pope Pius IX restored the Catholic hierarchy in England and Wales, with the creation of thirteen new dioceses.
As part of this restoration, the Catholic Diocese of Southwark was erected on 29 September 1850. The new Diocese of Southwark covered much of southern England - London south of the Thames, Surrey, Kent, Sussex, Berkshire, southern Oxfordshire, Hampshire and the Channel Islands. Bishop Thomas Grant was consecrated as bishop of the Diocese on 4 July 1851.
Two years prior to the restoration of the hierarchy, on 4th July 1848, St George’s Catholic Church, designed by Augustus Pugin, was solemnly opened by Bishop Wiseman. On the restoration, St George's was chosen as the Cathedral Church of the new Diocese of Southwark. For the next half-century, until the opening of Westminster Cathedral, St George's was the centre of Catholic life in London.
By the later 1800s, it had become clear that the Diocese of Southwark was too large for one bishop. On 19 May 1882, Pope Leo XIII created the Diocese of Portsmouth from the Diocese of Southwark. Hampshire, South Oxfordshire, Berkshire, and the Channel Islands became part of the new Diocese.
In 1888, Bishop John Butt purchased 60 acres of land in Wonersh, near Guildford and appointed Frederick Walters to design a Diocesan Seminary. St John’s Seminary opened in temporary accommodation at Henfield, Sussex in August 1889. Two years later, the new buildings were complete and the Seminary was officially opened on 8th September 1891.
On the night of 16 April 1941, St George’s Cathedral was hit by an incendiary bomb which started a fire that destroyed the Cathedral but left other Diocesan buildings on the site undamaged. The Cathedral was rebuilt, designed by the architect Romilly Craze, and consecrated on 4 July 1958 by Bishop Cyril Cowderoy.
On 28 May 1965, Pope Paul VI created a new Diocese of Arundel and Brighton from part of the Diocese of Southwark. East and West Sussex and Surrey (outside of the London boroughs) became part of this new Diocese. On the same date, the Diocese of Southwark was elevated to a Metropolitan See and Bishop Cyril Cowderoy became the first Archbishop of the Archdiocese of Southwark. The Province of Southwark includes the Dioceses of Plymouth, Portsmouth and Arundel and Brighton.
Following the resignation of Archbishop Emeritus Peter Smith on 10th June 2019, the Archdiocese of Southwark continues to be guided under the pastoral leadership of Archbishop John Wilson, who was installed as the Eleventh Bishop of Southwark and Fifth Archbishop of Metropolitan and See on 25th July 2019.
On 3rd July 2021, St John’s Seminary in Wonersh closed and the training of Diocesan priests moved to Allen Hall in Westminster Diocese.