Few researches have explored the production of pharmaceuticals from aquatic plants. Therefore, this study explored, for the first time, the phytochemical composition and bioactivities of ten aquatic plants. Aquatic plant shoots from various Nile River canals were collected, dried, and ground for aqueous extract preparation. Phytochemical composition and antioxidant capacity were assessed using DPPH assays. Extracts were tested for antiparasitic, antibacterial, anti-biofilm, and anticancer activities through standard in vitro assays, measuring IC50 values, and evaluating mechanisms of action, including cell viability and high-content screening assays. The results showed that the aquatic plants were rich in pharmaceutical compounds. The antioxidant capacity of these extracts exceeded that of vitamin C. The extracts showed promising antiparasitic activity against pathogens like Opisthorchis viverrini and Plasmodium falciparum, with IC50 values between 0.7 and 2.5 µg/mL. They also demonstrated low MICs against various pathogenic bacteria, causing DNA damage, increased plasma membrane permeability, and 90% biofilm inhibition. In terms of anticancer activity, extracts were effective against a panel of cancer cell lines, with Ludwigia stolonifera exhibiting the highest efficacy. Its IC50 ranged from 0.5 µg/mL for pancreatic, esophageal, and colon cancer cells to 1.5 µg/mL for gastric cancer cells. Overall, IC50 values for all extracts were below 6 µg/mL, showing significant apoptotic activity, increased nuclear intensity, plasma membrane permeability, mitochondrial membrane permeability, and cytochrome c release, and outperforming doxorubicin. This study highlights the potential of aquatic plants as sources for new, safe, and effective drugs with strong antiparasitic, antibacterial, and anticancer properties.