The present study aimed to evaluate the antimicrobial and antioxidant activities of Padina sp. and Sargassum sp. algae collected from the Gulf of Oman. Samples were obtained from the coast of Jask city in spring 2024. Algal extracts were prepared using a combination of soaking and ultrasonic bath methods. Antioxidant activity was assessed using the diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, while antimicrobial activity was determined by broth microdilution to measure the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The median antioxidant activities of aqueous and organic extracts were 80.93 ± 6.64 and 474.3 ± 41.53 µg/mL for Padina, and 65.87 ± 4.11 and 325.2 ± 2.26 µg/mL for Sargassum, respectively. The MICs of Padina organic extracts against Vibrio parahaemolyticus, V. alginolyticus, and V. harveyi were 256, 64, and 64 µg/mL, with MBCs of 512, 256, and 128 µg/mL, respectively. Aqueous extracts of Padina were less effective, with MICs of 512, 256, and 128 µg/mL and MBCs of 512 and 256 µg/mL. For Sargassum, the organic extract exhibited stronger antimicrobial activity, with MICs of 128, 64, and 128 µg/mL and MBCs of 256, 128, and 128 µg/mL, respectively. The MICs of aqueous Sargassum extracts were 256, 256, and 128 µg/mL. Overall, these findings confirm the antioxidant and antibacterial potential of Padina and Sargassum extracts, particularly their activity against pathogenic Vibrio species. These algae therefore represent promising candidates for development as dietary supplements in aquaculture