Glass bangles are found in southern England and Wales from the mid-first century ad and become common in the north of England and southern Scotland in the late first century, before their numbers decline a century later. British bangles develop at a time of change, as Roman glassmaking practices were introduced across large areas of Britain, and as blown, transparent, colourless and naturally-coloured glassware became increasingly popular. In many communities, however, there was still a demand for strongly coloured opaque glass, including for bangles, and glassworkers devised ways of extending their supplies of opaque coloured glass. This study is based on over one hundred and fifty analyses of bangle fragments from sites in Wales, northern England and southern Scotland, spanning this transitional period. The bangle makers recycled coloured glass from imported vessels, and probably beads and bangle-making waste, to supplement supplies of fresh coloured glass. The novel methods used to modify and extend the coloured glass may derive from pre-Roman bead-making industries, and made use of widely available materials, including smithing hammerscale and possibly plant ashes. The results show the shifting balance of indigenous and Roman influences on different bangle types, depending on when and where they were made, and by whom.