Seabed mineral resources have been found on the bottom of the ocean, and to utilize them, samples must be taken and analyzed. This study develops a seafloor robotic explorer that can excavate and sample seafloor soil. In a previous study, we developed a drilling robot that could excavate 430 mm into the ground while underwater. However, excavation deeper than 430 mm was not possible because the discharging outlet became buried, making it difficult to discharge the drilled soil. In this paper, we develop a discharging mechanism utilizing water jetting to improve the excavation depth to 650 mm and potentially deeper.