Ocean　wave　energy　is　a　promising　clean　and　renewable　energy　source　to　mitigate　the　global　energy　crisis　and　environmental　issues.　Here,　a　guided-liquid-based　isotropic　triboelectric–electromagnetic-hybrid　nanogenerator　(iTEHG)　is　developed　for　efficient　and　sustainable　harvesting　of　omnidirectional　ocean　wave　energy.　The　fully-enclosed　iTEHG　is　based　on　a　triboelectric　nanogenerator　(TENG)　and　electromagnetic　generator　(EMG),　with　the　structure　design　of　a　unique　concentric　circular　electrode　pair　built　on　a　tilted　satellite-dish-inspired　plate　for　gravity-guided　motion　of　the　liquid.　The　newly-designed　ocean　wave　harvester　solves　the　wear　and　insufficient　contact　problems　of　mainstream　solid–solid-interfaced　TENGs,　prolonging　the　device　lifetime,　and　improves　controllability　of　liquid　compared　with　other　solid–liquid-interfaced　TENGs.　This　produces　immediate　power　and　current　densities　of　7.25　µW·cm–3　and　4.85　µA·cm–3　with　undifferentiated　360°　coverage.　The　iTEHG　can　charge　a　0.1　F　supercapacitor　to　3.1　V　and　continuously　drive　a　wireless　thermometer　for　over　26　min.　It　exhibits　superior　performance　for　practical　applications　in　real　ocean　environments,　proven　by　continuously　driving　320　high　luminosity　LEDs　in　Sanya　Bay,　China,　even　during　quiet　periods　of　ocean　activity.　The　proposed　design　is　expected　to　have　a　broad　prospect　for　future　blue　energy　harvesting　and　inspire　development　of　self-sufficient　ocean　sensors.　©　2023　The　Authors