Plasticisers, such as phthalate esters and bisphenols, can be incorporated into plastic materials during manufacturing to tailor the mechanical and thermal properties of the plastics. However, plasticisers have been known to leach and migrate from plastic materials into their surroundings, and consequently have been detected in a plethora of environmental matrices worldwide, including oceans, lakes and tissues of aquatic animals. Furthermore, exposure to plasticised microplastics, both alone and in combination, can lead to physiological and behavioural impacts. Despite the ecotoxicity and leachable properties of plasticised microplastics, the large majority of research in this field has been conducted using consumer products under typical user conditions (e.g., the heat treatment of plastic packaging containers). In this study, the leaching of common phthalate ester and bisphenol plasticisers from microplastics were investigated under various aqueous environmental conditions (i.e., freshwater and marine) and leaching models established. Results obtained here will help us further understand how plasticised microplastics can impact water quality.