Triboelectric nanogenerators (TENGs) show immense potential for harvesting low-frequency, chaotic, high-entropy ocean wave energy, offering a reliable power source for low-power sensors distributed across marine environments. However, their development remains constrained by limited power output and friction-related wear challenges. Here, we introduce an oscillating float-type triboelectric nanogenerator (OF-TENG) that boosts output current via staggered alignment pairing (SAP) of triboelectric materials, coupled with a planetary gear and non-contact reciprocating rotary design, to effectively capture multidirectional low-frequency ocean wave energy. At 1 Hz low-frequency waves, the OF-TENG delivers an output current of 0.31 mA, a peak power of 111.56 mW, and an average volumetric power density of 21.58 W m−3. Leveraging its non-contact friction design, the OF-TENG sustains exceptional output stability after 60 hours (>9 500 000 cycles) of continuous operation, with no significant performance decline. Additionally, the OF-TENG successfully powers 1000 light emitting diodes, a wireless water quality monitoring system (measuring total dissolved solids, pH value, and temperature), and drives electrochemical water splitting, yielding a hydrogen generation rate of 16.04 μL min−1 after 30 min. This study propels the development of high-power-density OF-TENGs, underscoring their substantial potential for harvesting low-frequency and chaotic wave energy and energizing distributed sensors in marine Internet of Things applications.