The recent increase in nanoparticle (P25 TiO2 NPs) usage has led to concerns regarding their potential implications on environment and human health. The food chain is the central pathway for nanoparticle transfer from lower to high trophic level organisms. The current study relies on the investigation of toxicity and trophic transfer potential of TiO2 NPs from marine algae Dunaliella salina to marine crustacean Artemia salina. Toxicity was measured in two different modes of exposure such as waterborne (exposure of TiO2 NPs to Artemia) and dietary exposure (NP-accumulated algal cells are used to feed the Artemia). The toxicity and accumulation of TiO2 NPs in marine algae D. salina were also studied. Artemia was found to be more sensitive to TiO2 NPs (48 h LC50 of 4.21 mg L−1) as compared to marine algae, D. salina (48 h LC50 of 11.35 mg L−1). The toxicity, uptake, and accumulation of TiO2 NPs were observed to be more in waterborne exposure as compared to dietary exposure. Waterborne exposure seemed to cause higher ROS production and antioxidant enzyme (SOD and CAT) activity as compared to dietary exposure of TiO2 NPs in Artemia. There were no observed biomagnification (BMF) and trophic transfer from algae to Artemia through dietary exposure. Histopathological studies confirmed the morphological and internal damages in Artemia. This study reiterates the possible effects of the different modes of exposure on trophic transfer potential of TiO2 NPs and eventually the consequences on aquatic environment.