In the present study, the concentration of four steroidal estrogens (estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethinylestradiol (EE2)) was determined in two sewage treatment plants (STPs) and in surface marine water from Jeddah’s coast. The average removal efficiencies (REs) of steroidal estrogens ranged 46.7-89.5%, in King Abdulaziz University (KAU) STP. In the Al-Khumrah (AK) STP wastewater, the RE was 77.7-88.5%. In the marine water samples, E1 was the most frequently detected estrogen with concentrations ranging from not detected (ND) to 50 ng/L. E2 was detected in seven samples with variable concentrations up to 3.2 ng/L. E3 was detected in two samples from one site (0.8 and 1 ng/L), whereas EE2 was detected above limits of quantification (LOQ) in three samples with a maximum concentration of 1.9 ng/L in three different sites. Estrogen levels on the Red Sea coast were generally low compared to some published reports elsewhere. This study provides baseline data for steroidal estrogens occurrence and removal in STP wastewater and their concentrations in the coastal water likely impacted by STP effluents for the first time in the Middle East which lacks such data.