Bohai Bay, a typical semi-enclosed bay, is close to the Beijing-Tianjin-Hebei Region, the economic center of north China. The release of emerging contaminants was considerably increasing with the fast urbanization and industrialization along the coastline. However, such data, e.g. plastic polymers, are still limited. Here, polyethylene terephthalate (PET) and di-(2-ethylhexyl) phthalate (DEHP) in surface sediments and sediment cores from the coastal area of Bohai Bay were investigated. The ranges of PET and DEHP concentrations in surface sediments are 1.49–13.90 mg/kg and 0.23–19.26 mg/kg, respectively. The relatively high contents of PET and DEHP were found near the Haihe River estuary, indicating the importance of riverine input. The PET and DEHP profiles in the cores dated by the ²¹⁰Pb method showed increasing trends with time. The PET in Bohai Bay was low risk evaluated by the potential ecological risk assessment. Low ecological risks of DEHP to the benthic organisms were found in the sediments, using the environmental risk limits, risk quotient, threshold effect level and probable effect level methods. The pollution levels of PET and DEHP in Bohai Bay obtained in this study may provide important data for making pollution control strategies.