Wastewater treatment plants are considered to be one of the largest sources of microplastics in the natural environment. The problem of microplastics has been widely studied in many environments. It remains a subject of the growing interest for researchers. By definition, microplastic is plastic that does not exceed 5 mm in size. There are three stages in the study of microplastics in wastewater: sampling, treatment, and the identification of microplastics. This paper aims to review the strategies for sampling microplastics in wastewater treatment plants and their laboratory treatment to isolate microplastics. The collection of samples from the wastewater treatment plant is based on two mechanisms, namely a continuous filtering and pumping system and instantaneous sampling (steel bucket, glass jar, telescopic sampling). The removal of organic and inorganic matter is carried out with the use of physical and chemical analyses. The subject of this article is the compilation of the generally available research methods on microplastics. Based on the literature analysis, conclusions were drawn regarding the recommended methods of microplastic detection.