Triboelectric nanogenerators (TENGs) have been widely reported as a means of transforming mechanical energy into electricity to charge small devices in the environment. However, the effect of the working environment, such as high humidity, rain, snow, and dust or particulates, on the stability of TENG performance can hamper their practical application. Herein, a novel enclosed and flexible interconnected TENG array was designed to protect it from the external environment, allowing it to effectively operate in humid conditions and even function in water. Furthermore, the influences of surface morphology of the triboelectric layer and various structural factors of each TENG unit on the output performance were optimized and analyzed. The designed interconnected TENG array composed of multiple TENG units showed a higher output performance and sensitivity compared with more common independent TENG arrays because the air pressure inside each TENG unit was optimized. Consequently, the interconnected TENG array could be applied for gait monitoring, self-powered waterproof keyboards, and mechanical energy harvesting applications from a variety of sources, such as related to rain, wind, or impact vibration. The novel interconnected TENG array composed of multiple TENG units showed greater output performance and sensitivity compared with the more commonly used independent TENG because of optimization of the air pressure in each TENG unit. The interconnected TENG array was demonstrated in a smart shoe insole, a self-powered waterproof keyboard, and for a variety of mechanical energy harvesting. • The novel interconnected TENG array composed of multiple TENG units showed greater output performance and sensitivity. • The interconnected TENG array allowed to be effectively used in high humidity conditions or even in water. • It is proved that the triboelectric charges has nothing to do with the electrical properties of the external contact objects.