A low-viscosity ternary natural deep eutectic solvent (NADES) composed of menthol, camphor and thymol, was developed as a sustainable extractant for the determination of methyl-, ethyl-, and propyl-paraben (MP, EP, PP), triclosan (TCSN), and 4-tert-octylphenol (4-t-OPH) in wastewater by UHPLC-DAD. Spectroscopic (FTIR, 1H NMR) and rheological characterization confirmed the formation of a stable hydrogen-bonded eutectic phase with markedly reduced viscosity, enabling direct chromatographic injection without dilution or back-extraction. The extraction process was optimized considering agitation mode, pH, ionic strength, extractant volume, and contact time. R-AE at neutral pH, 0.5 % Na2SO4, 300 μL of NADES, and 40 min extraction time provided the best analytical response. The method exhibited excellent linearity (R2 > 0.994), MLOD 0.03-0.85 μg L-1, MLOQ 0.11-2.13 μg L-1, and precision RSD <9 %, with recoveries of 84-117 % across wastewater treatment stages. MP, EP, and PP were detected in real samples at decreasing concentrations from primary to tertiary effluent, consistent with their expected biodegradation profiles, while TCSN and 4-t-OPH remained below MLOD. The AGREEprep assessment (score = 0.71) confirmed the method's superior greenness compared with other DES and solvent-based UHPLC-DAD microextraction techniques. Overall, the menthol:camphor:thymol (MCT) NADES offers a viable, eco-efficient, and cost-effective alternative for the routine monitoring of endocrine-disrupting PCPs in aquatic environments, advancing green analytical chemistry in wastewater analysis.