To address water scarcity in arid and semi-arid regions like Egypt and enhance food security, a research trial was conducted to assess the impact of different irrigation rates, soil addition of biochar, and foliar applications of trehalose and seaweed on the enzyme activity, yield and quality of potato. Three irrigation levels: 100% (I1), 80% (I2) and 60% (I3) of the irrigation requirements, with biochar applied at 0.0, 5.0, and 7.0 m3 fed-1, as well as spraying trehalose and seaweed at a concentration of 1.0 g/L, in addition to the control treatment, were investigated. The I3 treatment led to the highest levels of PPO,CAT and MDA, while the I1 treatment resulted in the lowest values. Increasing biochar rates reduced enzyme activity, and foliar applications of trehalose and seaweed further decreased these enzyme levels compared to the control. Even under reduced irrigation conditions, trehalose and seaweed application combined with biochar improved plant growth parameters such as plant height, and fresh and dry weights compared to traditional irrigation (I1 treatment) in the absence of both biochar and foliar applications. The highest tuber yield and quality traits, including total carbohydrates, total sugars, protein percentage and vitamin C content, were achieved under the combined treatment of I1 x biochar (7.0 m3 fed-1) x trehalose. Notably, the I2 treatment combined with biochar and either trehalose or seaweed outperformed the I1 treatment without additional treatments. This study suggests that integrating biochar with foliar treatments of trehalose and seaweed can significantly enhance potato production under water-limited conditions.