The concentrations and spatial distribution of 14 organophosphorus flame retardants (OPFRs) and plasticizers were studied in aquatic environments of China, namely, the Pearl River Delta (PRD), South China Sea (SCS) and Yellow River Estuary (YRE), as well as Tokyo Bay (TB) in Japan. These locations were characterized by different levels of socioeconomic development and human activities. The spatial pattern of OPFRs revealed their ubiquity along the coasts of China and Japan; the concentrations ranged from 15 to 1790, 1 to 147, 253 to 1720, and 107 to 284 ng L-1 in the PRD, SCS, YRE and TB, respectively. The most frequently detected OPFR was triethyl phosphate (TEP), followed by triphenylphosphine oxide (TPPO) and tris(2-chloroethyl) phosphate (TCEP). A positive relationship (R2 = 0.668, p = 0.004) was observed between OPFR contamination and socioeconomic activity, measured by gross domestic product (GDP) per capita, for the studied cities in China and Japan. The results suggest that an increase in manufacturing and construction activities in the studied areas may aggravate coastal contamination with OPFRs. The potential threat to aquatic organisms from exposure to TCEP, a suspected carcinogen, was revealed by the hazard quotient (HQ) and probabilistic assessments. Further investigation of OPFR exposure in the aquatic environment of China is urgently required.