The diocesan bishop of Canterbury is the Archbishop of Canterbury. But the Archbishop also serves as Metropolitan Bishop of the Province of Canterbury, Primate of All England, and first bishop of the worldwide Anglican Communion - which keeps them mostly in London, mostly at Lambeth Palace, mostly away from the diocese itself. So the day-to-day work falls largely to a suffragan bishop, the Bishop of Dover. The current Bishop of Dover, Rose Hudson-Wilkin, is empowered to act almost as if she were the diocesan bishop, leading what is essentially a national church's local church. Until 2010 the diocese also had a Bishop of Maidstone in a similar role, but that post was discontinued. Two further suffragan bishops have nominal sees within the diocese - Ebbsfleet and Richborough - though their work as provincial episcopal visitors extends far beyond Canterbury.

The diocese covers most of eastern Kent and contains 202 parishes organised into 100 legal benefices, divided across three archdeaconries and sixteen deaneries. The Deanery of Canterbury alone holds parishes whose churches were founded before the Norman Conquest. St Martin's Church in Canterbury, which serves as parish church for Canterbury St Martin and St Paul, was built by Bertha's Frankish chaplain before Augustine arrived, making it - by some measures - the oldest church in the English-speaking world still in use. Saxon St Pancras' Church, also in Canterbury, has been closed for centuries but its remains can be visited at St Augustine's Abbey. The list of medieval churches that opened, closed, were demolished by Henry VIII, were destroyed by Luftwaffe bombs in 1942, or were quietly closed by twentieth-century redundancy is itself a compact history of English religion.

Eastern Kent is unusually dense with founder-saints. Lyminge contains the church of SS Mary and Ethelburga, named for the Kentish princess who became Queen of Northumbria and brought Christianity north. Reculver - now visible as ruined twin towers on a clifftop - was founded by Bassa in 669 over the site of a Roman Saxon Shore fort. Minster-in-Thanet still bears its medieval church of St Mary the Virgin. Brookland's St Augustine of Canterbury Church on Romney Marsh has an extraordinary detached wooden bell tower. The Deanery of Romney runs across the strange flat marshlands of southern Kent, where medieval churches stand isolated among the sheep pastures, sometimes with their original wall paintings still visible inside. The Deanery of Thanet covers the resort towns of Margate, Broadstairs, and Ramsgate. The Deanery of Dover holds the parish of The Langdons, with the church of St Augustine of Canterbury at East Langdon - named for the same Augustine who landed at nearby Ebbsfleet in 597.

Hundreds of medieval churches stood inside the Diocese of Canterbury at its peak. Many are gone. The Dissolution of the Monasteries in the 1530s closed monastic foundations across the diocese. The Reformation closed some parish churches. The Baedeker Blitz of 1942 destroyed several - St George the Martyr's in Canterbury, the medieval St Mary Bredin Old Church, the Old Holy Trinity Church in Margate, the medieval St Mary's Old Church at Little Chart. Twentieth-century redundancy closed others. Yet the diocese also planted new parishes throughout the 19th and 20th centuries to serve growing populations - 1840s churches in seaside resorts, 1950s churches in housing estates, 2007 in Seasalter. The pattern is one of constant pruning and constant new growth, the diocese as a living thing rather than a museum.

Canterbury Cathedral itself sits at the centre of all this - the seat of the Archbishop, the focus of the diocese, the mother church of around 85 million Anglicans worldwide. Founded in 597 by Augustine on a site that may have been an earlier Romano-British church, rebuilt by successive archbishops, expanded in the great medieval campaigns that produced the choir, the nave, and finally the Bell Harry Tower of 1498, the cathedral has been a working place of worship for fourteen centuries. Services are held three or more times each day - matins, eucharist, and evensong - the same daily round Augustine's monks would recognise. A million tourists visit each year, but the diocese is not the tourists. The diocese is 202 parishes spread across the lanes and marshes and seaside towns of eastern Kent, where the work of Christianity, begun under that oak tree in 597, has gone on quietly and unbrokenly ever since.