The last interglacial serves as an excellent time interval for studying climate dynamics during past warm periods. Speleothems have been successfully used for reconstructing the paleoclimate of last interglacial continental Europe. However, all previously investigated speleothems are restricted to southern Europe or the Alps, leaving large parts of northwestern Europe undocumented. To better understand regional climate changes over the past, a larger spatial coverage of European last interglacial continental records is essential, and speleothems, because of their ability to obtain excellent chronologies, can provide a major contribution. Here, we present new, high-resolution data from a stalagmite (Han-9) obtained from the Han-sur-Lesse Cave in Belgium. Han-9 formed between 125.3 and similar to aEuro parts per thousand aEuro-97aEuro-ka, with interruptions of growth occurring at 117.3-112.9 and 106.6-103.6aEuro-ka. The speleothem was investigated for its growth, morphology and stable isotope (delta C-13 and delta O-18) composition. The speleothem started growing relatively late within the last interglacial, at 125.3aEuro-ka, as other European continental archives suggest that Eemian optimum conditions were already present during that time. It appears that the initiation of Han-9 growth is caused by an increase in moisture availability, linked to wetter conditions around 125.3aEuro-ka. The delta C-13 and delta O-18 proxies indicate a period of relatively stable conditions after 125.3aEuro-ka; however, at 120aEuro-ka the speleothem delta O-18 registered the first signs of regionally changing climate conditions, being a modification of ocean source delta O-18 linked to an increase in ice volume towards the Marine Isotope Stage (MIS) 5e-5d transition. At 117.5aEuro-ka, drastic vegetation changes are recorded by Han-9 delta C-13 immediately followed by a cessation of speleothem growth at 117.3aEuro-ka, suggesting a transition to significantly dryer conditions. The Han-9 record covering the early Weichselian displays ...