The dataset contains detrital zircon U-Pb ages for the Llanbedr (Mochras Farm) borehole, from the Lower Jurassic. The U-Pb zircon age analyses was carried out on the SHRIMP IIe/MC instrument (the sensitive high resolution ion microprobe) at the Polish Geological Institute, Warsaw. Data relate to the Llanbedr (Mochras Farm) Borehole drilled in 1967-1969 near the village of Llanbedr, NW Wales, SH 5533 2594. The aim for generating these data was to provide evidence for sediment provenance to the Llanbedr (Mochras Farm) site during the Early Jurassic. Publication in press, Jiang et al. (2026) Laurasian Seaway history during the Early Jurassic from quantitative mineralogy and detrital zircon dating. Paleoceanography and Paleoclimatology.