Small volcanic eruptions are often poorly preserved in the geological record, yet they can provide key insights into the magmatic processes that drive regular unrest and activity. Here, I describe the results from a range of petrological tools to explore the magma processes that drive past eruptions at New Zealand’s most active volcano – Whakaari/White Island. Understanding the magmatic system runs in tandem with our developing understanding of its hydrothermal system, in the hope that we can better understand unrest signals prior to eruption. White Island is a largely submerged island that has been active since observations were recorded back in the 1800’s and it has been in a near constant state of unrest, punctuated by small volume magmatic, phreatomagmatic, and phreatic eruptions. My work provides an important link between magma processes, the inputs to the hydrothermal system, volcano monitoring, and eruption forecasting.