Seawater electrolysis (SWE) is proposed to be a promising approach to green hydrogen (H2) production but its large‐scale deployment faces challenges because of the anodic competing chlorine evolution reaction (CER) and high energy consumption. To address these challenges, innovative hybrid SWE systems have recently emerged, able to mitigate the interference of CER and substantially reduce the electrical energy needed. Herein, the preparation of 2D layered PtTe nanosheets (e‐PtTe NSs) using the liquid‐phase exfoliation method is reported, which show outstanding electrocatalytic performance for the hydrogen evolution (HER), hydrazine oxidation (HzOR), and oxygen reduction reactions (ORR) in seawater. Using e‐PtTe NSs as trifunctional catalysts, two hybrid SWE systems are demonstrated: 1) a hydrazine‐assisted acid‐alkaline dual‐electrolyte seawater electrolyzer enabled by a bipolar …