Microplastics (PM) are a major source of pollution in the oceans due to their ubiquity and their high absorption capacity for dangerous hydrophobic substances, including persistent organic pollutants (POPs). Ingestion of PM can contribute to the absorption of POPs by marine organisms and their biomagnification through the food web. The whale shark (Rhincodon typus) is a filter organism susceptible to ingest floating PM and POPs bound to PM during its foraging activity. This species is included in Appendix II of CITES and endangered on the IUCN Red List. Bahía de los Angeles (BLA) in the Gulf of California is a sighting site for this species in Mexico. The objective of this study is to evaluate the presence of toxic PM and POPs in BLA whale sharks in biopsies of subcutaneous tissues and zooplankton.