Ocean alkalinity enhancement is a promising method for large-scale marine carbon dioxide removal (mCDR). This method mimics the natural process of weathering to induce a deficit of CO2 at the surface of the ocean, resulting in enhanced uptake of CO2 from the atmosphere. Recently, a small-scale field trial was undertaken tracking a plume of continuously pumped seawater, modified through inline addition of aqueous sodium hydroxide, into the coastal ocean of southern Tasmania. We present the findings from this trial, including: the experimental system and in-situ instrumentation; baseline observations of the CO2 system before and after the trial; the spatial and temporal extent of the alkalinity perturbation; coupling with a regional hydrodynamic and biogeochemical model; and recommendations for future work. We also share our experience collaborating with the local community and working with regulatory and permitting authorities in the region.