Looking for a biotechnical potential, aqueous extracts of leaves of 12 native species used in the Mayan traditional medicine of the coastal dune and mangrove of Yucatan (Mexico) were selected to evaluate their biological activities. Rhizophora mangle and Manilkara zapota showed the highest free radical scavenging activity (3.94 ± 0.19 and 6.42 ± 0.32 μg/mL, respectively), and the highest antihypertensive activity was obtained from Solanum donianum (0.38 μg/mL). The anti-hyperglycemic activity of these species was also tested; the highest activities were registered with R. mangle. The antimicrobial activity of Malvaviscus arboreus, S. donianum, M. zapota, and R. mangle at 10% (w/v) was positive against six human pathogenic bacteria and Bonellia macrocarpa against one pathogenic fungus. Solanum donianum, M. zapota, B. macrocarpa, and R. mangle were positive against two pathogenic plant fungi. These results show that the aqueous extracts of five native plants of the Yucatan coast have potential as antioxidants, ACE inhibitors, α-amylase and α-glucosidase inhibitors, and as antimicrobials, which make their exploration for utilization in the agricultural and pharmaceutical industries a possibility.