Alginate, a naturally occurring biopolymer derived from the cell walls of brown algae, is widely utilized in biotechnology and biomedical fields due to its ability to encapsulate cells or enzymes within microcapsules. These microcapsules, which are small spherical particles ranging from a few micrometres to millimetres in size, offer protection and stabilization of their core substances under various environmental conditions. This study investigates the characterization of fabricated single-layer alginate microcapsules, focusing on their stability under varying environmental conditions, including temperature, pH, and relative humidity. The results indicate that the size of the microcapsules gradually increased as the temperature rose from 5 to 85 °C. The microcapsules remained stable at pH levels of 3, 5, and 7, showing no change in size, however higher pH levels led to an increase in size and eventual capsule rupture. Water absorption tests revealed that higher relative humidity levels increased water absorption within 120H, but at 90% relative humidity, the absorption pattern decreased, suggesting saturation of the microcapsules. These findings enhance the understanding of the physical and mechanical properties of single-layer alginate microcapsules, which is essential for optimizing their formulation to improve integrity and better control the release mechanisms of encapsulated components in practical applications.