Atmospheric new particle formation (NPF) is crucial for aerosol number concentration and for studying the production processes of secondary aerosol particles. NPF events are commonly classified based on visible particle growth, and their occurrence frequency is often underestimated. Recent methodologies propose that "quiet" NPF (QNPF) events, which are not traditionally classified as NPF events, can contribute significantly to particle number concentrations. This study presents three-years (June 2020–May 2023) of observations of ion and particle size distributions performed at the Finokalia environmental research station in Crete, Greece, using a Neutral cluster and Air Ion Spectrometer (NAIS) and a Mobility Particle Size Spectrometer (MPSS). By analysing the observed ion number size distributions and applying a nanoparticle ranking analysis method, this study reveals that QNPF events are frequent and contribute significantly to particle formation and growth in the Eastern Mediterranean. Negatively charged intermediate size ions are found to be reliable indicators of particle formation, including both classical NPF and QNPF episodes. Our analysis indicates continuous particle formation even on days traditionally classified as "non-event" days, providing fundamentally new understanding of NPF processes in the region.