The western seaways – an arc of sea stretching from the Channel Islands in the south, up through the Isles of Scilly, the Isle of Man, and the Outer Hebrides to Orkney in the north – have long been seen as crucial to our understanding of the processes which led to the arrival of the Neolithic in Britain and Ireland in the centuries around 4000 cal bc. The western seaways have not, however, been considered in detail within any of the recent studies addressing the radiocarbon chronology of the earliest Neolithic in that wider region. This paper presents a synthesis of all existing 5th and 4th millennia cal bc radiocarbon dates from islands within the western seaways, including 50 new results obtained specifically for this study. While the focus here is insular in a literal sense, the project’s results have far reaching implications for our understanding of the Mesolithic–Neolithic transition in Britain and Ireland and beyond. The findings broadly fit well with the Gathering Time model of Whittle et al., suggesting that the earliest dated Neolithic in this zone falls into the c. 3900–3700 cal bc bracket. However, it is also noted that our current chronological understanding is based on comparatively few dates spread across a large area. Consequently, it is suggested that both further targeted work and an approach that incorporates an element of typo-chronology (as well as absolute dating) is necessary if we are to move forward our understanding of the processes associated with the appearance of the first Neolithic material culture and practices in this key region.