The name Beccles first appears in the Domesday Book of 1086 as Becles, and the etymology is straightforward Old English: bec-laes, meaning pasture on the stream, with bec cognate to the German Bach for stream and laes related to the English word lea for meadow. The town sits in the Waveney valley on the edge of The Broads National Park, sixteen miles southeast of Norwich and the same distance inland from the coast at Great Yarmouth. Elizabeth I granted Beccles its first charter on 2 July 1584, formalising what had clearly been an Anglian river port for centuries. James I confirmed the charter in 1605. The town centre's streets carry Old Norse fingerprints: Ballygate, Smallgate, Blyburgate, the gate suffix coming from the Norse for street, similar to the modern Danish gade. The population at the 2021 census was 10,069. Most days the river is busy with boats, the Broads reaching this far up the Waveney.

The detached bell tower of St Michael's Church dominates the townscape. Ninety-seven feet of Perpendicular Gothic stonework, built in the sixteenth century, deliberately separated from the main church building. The decision to build the tower as a freestanding structure was unusual then and remains unusual now. Both the tower and the church are Grade I listed. The church itself dates from the fourteenth century, was badly damaged by fire in 1586, and rebuilt afterwards. It retains a thirteenth-century octagonal baptismal font and a fourteenth-century south porch. South of the town centre on Ballygate stands Leman House, another Grade I listed sixteenth-century building, now home to Beccles Museum. The house was the original site of the town's Grammar School, endowed by John Leman, a tradesman from Beccles who became Lord Mayor of London and died in 1632. Sir John Leman High School in the town still carries his name.

The Peck family of Beccles has woven through centuries of the town's history, including recent mayors. One Peck in particular travelled far. The Reverend Robert Peck, described in the local histories as a man of violent schismatic spirit, led a Puritan movement at the church of St Andrew's in Hingham, Norfolk, in opposition to established Anglicanism. Forced into exile, Peck fled to Hingham, Massachusetts, a town named and partly founded by members of his original Norfolk parish. He stayed there until Charles I had been executed and Cromwell was in power, then returned to Norfolk and resumed as rector. He died in Hingham, Norfolk. His brother Joseph Peck settled in Rehoboth, Massachusetts, founding a family line in New England. Robert's daughter Ann Peck remained in Massachusetts and married John Mason, who led colonial forces in the Pequot War. That war was a brutal episode in seventeenth-century colonial history, and the Pequot people who lived through it experienced devastating violence and dispossession. The Beccles connection to it runs through one woman who left this Suffolk town and never returned. In 1794 the French émigré François-René de Chateaubriand worked here as a French teacher and fell in love with Charlotte Ives, the daughter of a clergyman from nearby Bungay.

Beccles has produced an unusual concentration of nationally known figures. Dorothy Hodgkin, who won the 1964 Nobel Prize in Chemistry for her work using X-ray crystallography to determine the structures of biochemical compounds including penicillin and vitamin B12, has connections to the town. So do Claude Auchinleck, the general who commanded British forces in India and North Africa during the Second World War; the broadcaster David Frost; the BBC journalist Martin Bell; the obstetrician Grantly Dick-Read, who championed natural childbirth; Tim Buck, General Secretary of the Communist Party of Canada from 1929 to 1962; the children's historical novelist Hester Burton; the philologist William Aldis Wright; the swimmer Jordan Catchpole, who won gold at the 2020 Paralympics; and Boney's Island, a man-made mound on the common whose name comes from Napoleon, either because of a prisoner-of-war camp held there during the Napoleonic Wars or because of a celebratory bonfire lit in 1814 when those wars ended. The town carries the everyday work of a market town and the residual weight of many lives that started here and ended up elsewhere.