Is duct tape waterproof?

Flex Super Wide Duct Tape is water-resistant; however, it is not fully waterproof. This powerful duct tape has a tough, reinforced backing that is water, weather, and UV-resistant, but it isn’t designed for use on active leaks or submerged surfaces.

If you need 100% waterproof tape, especially for wet or underwater applications, Flex Tape should be your choice.