Triploid bivalves are increasingly favored in aquaculture due to their rapid growth and reduced investment in gametogenesis, which ensures steady market quality during the spawning season while minimizing ecological impacts on wild populations. The use of non-chemical methods to induce triploidy remains challenging, often resulting in low triploid yields and reduced larval survival. As consumer and industry preferences shift toward non-chemical treatments, refining these methods is essential for sustainable aquaculture. This study aimed to determine the optimal hydrostatic pressure shock treatment in the blue mussel (Mytilus edulis) to maximize triploidy induction while minimizing negative effects on larval survival and development. A series of experiments manipulating critical variables, namely time post-fertilization, pressure, and duration of the pressure treatment, were carried out using the timing of the polar body extrusion as a reference (Figure 1). Triploidy was confirmed via flow cytometry, and full-sibling diploid controls were produced for comparison. Survival and growth were measured every two days until competent larvae were observed (<28 days). Following this, experiments with different sources of mussels and temperatures were further carried out to examine the robustness of the optimal protocol (Figure 1). By refining the protocol for the hydrostatic pressure triploid induction method, this study provides valuable insights into the potential use of triploid mussels in aquaculture settings. The findings suggest that timing adjustments can significantly enhance triploid success, larval survival, and overall growth and ultimately offer a reliable technology for optimizing mussel production, benefiting both farmers and the industry.