High-resolution (0.1 C, 0.5 m) aerial thermal infrared (TIR) imagery from the dry western coasts of the large volcanic island of Hawaii provides exact locations and fine-scale mixing structures of both diffusive flows and more than 50 buoyant submarine groundwater discharge (SGD) point-sourced “plumes” dispersing into the ocean. The plumes are cool, brackish, nutrient-rich groundwaters injected into and floating on top of warm tropical seawater. SGD fluxes were estimated using continuously-measured 222Rn and salinity for six of the largest discharge locations. We then used a proportionality between plume surface area discharge rate of the larger plumes to approximate individual flux estimates for all and each of the individual groundwater plumes mapped, and, for 65 km of coastline, we estimate a cumulative total groundwater (mixed fresh and marine) flux from 42 point-source groundwater inputs to be about 260,000 cubic meters/day. Estimated SGD nutrient fluxes for this dry, relatively pristine setting rival Hawaiian river outputs, are of comparable magnitude to that reported for rather heavily populated coastlines elsewhere, and are the only source of new nutrients available to this region’s coastal ocean.