Two methods based on high-performance liquid chromatography and atmospheric pressure chemical ionization mass spectrometry have been developed for determining phthalates and bis(2-ethylhexyl)adipate in water and marine sediment samples. A solid-phase extraction method using Isolute ENV+ as sorbent has been optimised for water samples and an ultrasonic extraction with acetonitrile was used to extract the compounds from sediment samples. In the solid-phase extraction method, 100 mL of sample containing a 20% of acetonitrile was preconcentrated. Under these conditions, recoveries were between 32 and 95% and the quantification limits ranged from 0.03 to 4 μg L−1. To analyse sediment, 1 g of sample was extracted and recoveries were up to 70% for all the compounds, and standard addition calibration was carried out. When these methods were applied to real samples, no compound was detected in the coastal water samples. In treatment plant wastewater, five compounds were quantified at concentration levels between 0.2 and 3.8 μg L−1, while in sediment samples, five compounds were quantified at concentration between 0.13 and 9.4 mg kg−1.