Selective targeting of specific cells without the use of biological ligands has not been achieved. In the present study, we revealed that the coacervate droplets formed from poly(2-methoxyethyl acrylate) (PMEA) and its derivatives selectively accumulated to tumor cells. PMEA derivatives, which are insoluble acrylate polymers, induced coacervation in water to form polymer-dense droplets via hydrophobic interaction. Interestingly, the accumulation of coacervate droplets to tumor cells was involved in the bound water content of PMEA derivatives. Coacervate droplets with a high bound water content accumulated and internalized up to 36.6-fold higher in HeLa cervical tumor cells than in normal human fibroblasts (NHDF). Moreover, the interactions between coacervate droplets and plasma membrane components such as CD44 played a key role in this accumulation process. Therefore, coacervate droplets formed from PMEA derivatives have great clinical potential in tumor cell detection, development of alternative tumor-targeting ligands, and optimization of drug delivery carriers.