This dataset contains bottom-up LC-MS/MS data from the culture-supernatant-derived extracellular protein fraction of Filobasidium magnum PLANB_3024 cultivated in the presence of poly(lactic acid) (PLA). Proteins were identified using Proteome Discoverer v3.0 with Sequest HT against a strain-specific protein database containing 9,413 predicted proteins derived from the PLANB_3024 genome. The dataset was generated to characterize extracellular proteins detected during growth in the presence of PLA, including a cutinase-family protein supported by peptide-level evidence.