For high-resolution regional geodetic applications, the International Terrestrial Reference Frame (ITRF) is complemented by regional densifications. These are realised either as multi-year solutions related to a tectonic plate (e.g., EUREF for Europe) or as epoch reference frames (ERFs) to capture non-linear geophysical effects like earthquakes or loading displacements (e.g., SIRGAS for Latin America). These GNSS-only-based regional frames have in common that their geodetic datum is aligned with the ITRF datum at a specific epoch. Their origin is thus geocentric only in a mean sense and does not always coincide with the instantaneous centre of mass. Here, we present studies on a direct geocentric realisation of regional ERFs. We propose to realise the geodetic datum for each epoch by combining global GNSS, SLR and VLBI networks via measured local ties at co-located sites. An equally-distributed global GNSS network is used to realise the orientation via a no-net-rotation constraint and is densified by the stations of the regional subnetwork. The developed combination and filtering strategy aims to guarantee a stable datum realisation for each epoch-wise solution. The effectiveness of our methods is validated against the current operational realisation of the SIRGAS Latin American reference frame. Comparing with geophysical loading models relating to the Earth’s centres of mass and figure, we show that the realised geocentric displacement time series directly reflect seasonal geophysical processes. Moreover, as the approach does not need to rely on co-location sites in the region of interest, it is conceptually transferrable to other global regions.