Chemical pollution poses a growing threat to wildlife and ecosystems globally. However, wild organisms are also exposed to other challenges that might shape the way that they respond to environmental pollution. Parasites, for instance, are widespread across ecosystems and are known to affect their hosts differently depending on environmental conditions, such as resource abundance. Yet how global contaminants alter host-parasite dynamics remains largely unknown. To fill this gap, we tested the combined effect of a widespread organic pollutant (phenanthrene; C₁₄H₁₀) and cestode parasites (Flamingolepis liguloides) on ecologically relevant behaviours and life-history traits of wild-caught brine shrimps (Artemia parthenogenetica). We exposed individuals to realistic concentrations of phenanthrene – one of the most abundant polycyclic aromatic hydrocarbons in aquatic environments worldwide – and repeatedly assessed their swimming activity (i.e., distance moved and time spent swimming) and risk-taking (i.e., time spent near the water surface and escaping behaviour). These behaviours are key determinants of parasite transmission in brine shrimps and affect their predation risk by flamingos, the final host of the parasite. Our results show that phenanthrene exposure significantly reduced swimming activity, while parasite load explained variation in risk-taking, with infected individuals spending more time near the water surface compared to uninfected ones. Our evidence provides novel insights into the interplay between pollution and parasites, highlighting the importance of considering more realistic environmental conditions when evaluating the ecological consequences of contaminants.