In order to ensure the excellent properties of duplex stainless steels regarding strength, toughness and corrosion resistance, the weld seams have to exhibit a microstructure of ferrite and at least of 30 \% of austenite. In this study, the application potential of the novel welding procedure laser beam-submerged arc hybrid welding was investigated for process-reliable and efficient joining of the duplex stainless steel S31803 with a thicknesses t of 16 mm, 20 mm and 30 mm. This welding process combines the advantages of laser beam welding and submerged arc welding. In context of the development of welding processes, suitable welding parameters can be determined depending on the welding configuration. For joining of the duplex steel S31803 with a thickness of t = 16 mm single run and with thicknesses t of 20 mm and 30 mm two runs were utilized. Based on the cross-sections, the weld seams show no imperfections with the exception of few small pores in the laser-dominated zone of the two-layer weld seams. The weld seams can be classified in the highest evaluation group B of the DIN EN ISO 12932 standard. Furthermore, the weld seams fulfil the requirement with respect to the austenite content of at least 30 \% with exception of weld seams of duplex stainless steel with a thickness of t = 30 mm due to low penetration of the filler material in the laser-dominated zone. Nevertheless, all weld seams archive the required impact energy of at least 40 J at a test temperature of −40 °C. As a concrete example, the weld seams of duplex stainless steel with a thickness of t = 16 mm archive an impact energy of 131 J, even by using a high welding speed of 1.0 m/min. Based on these results, laser beam-submerged arc hybrid welding has been shown to be a welding procedure with high productivity, which can play an important role in the future for the welding production of duplex stainless steel parts.