We here present 33 new AMS measurements on human and animal bone from eight court tombs and two monuments with passage tomb affinities. While some determinations confirm earlier Neolithic use, others relate to Early Bronze Age burial activity. Unexpectedly, the animal bone dates all fall within the second millennium AD. The results are discussed in the context of the known corpus of court tomb dates, a critical assessment of which suggests that many early charcoal dates should be discounted. Bayesian modelling of 47 determinations from twelve sites places the initial use of court tombs-and by extension their construction-in the period 3700-3570 cal. BC, a time that is emerging as very dynamic, with strong peaks in activity in both the mortuary and settlement spheres across Ireland and Britain. Stable isotope data also obtained continue to support the pattern of little or no use of marine protein in coastal areas in the Irish and British Neolithic.