This study employed transmission electron microscopy (TEM) to conduct research on the ultrastructure of watermelon (cultivar: Hazera SW1) mesocarp samples of different maturities. Micrographs from immature fruit showed incompletely formed chromoplasts. A combination of distinct pigment-bearing chromoplasts and incompletely formed chromoplasts was observed in mature watermelon micrographs. Electron micrographs showed chromoplasts changing from a less organized globular form in immature to a symmetrical form in mature to an asymmetrical form in overmature watermelons. This study furthers our understanding of watermelon physiology and the effect of maturity on compartmentalization of lycopene.