<p>Mycelium-based materials (MBMs) are a new type of biomaterial made of mycelium and lignocellulosic wastes. Due to their environmental friendliness, they offer an alternative to expanded polystyrene (EPS) as packaging materials. This study assessed the effects of compaction on MBMs’ characteristics. Three mycelium-generating strains and three types of substrates were utilized to produce MBMs using different protocols. As part of the various protocols compacted samples and uncompacted samples were applied. The physical and mechanical properties of MBMs are essential for their application in the packaging industry. Dry density, water absorption, and compressive properties were compared between MBMs with applied compaction and those without compaction. Compacted samples in this study showed a 9.57–34.29% increase in dry density, but the value was still lower than that of pulp moulding packaging (0.2–1.0 g/cm³), a commonly used green packaging material nowadays. Compacted samples also saw a 28.57–129.63% increase in compressive strength at 10% strain, a 37.32–139.42% increase at 35% strain, and a 27.66–142.35% increase in compressive Young’s modulus. The impact of compaction on the water absorption of the MBM samples varied depending on the samples’ recipes/composition. At 60% RH, the weight gain ranged from 4.49 to 7.21% and 4.59% to 6.98% for samples without compaction and with compaction, respectively. At 80% RH, the weight increase of uncompacted and compacted samples was 10.68–15.42% and 11.02–19.04%, respectively.</p>