The optimization of OWC devices has deserved much attention in the last few years. However, despite of this intense research activity, the most suitable turbine for OWC applications is still under debate. Recently, the twin-turbine configuration, where two unidirectional turbines are employed simultaneously, has emerged as a promising design. Although axial turbines are typically employed for those systems, the present paper demonstrates that the use of radial turbines can be also an interesting option. In this work a radial geometry, specifically designed to be used in a twin-turbine configuration, has been manufactured at a reasonable cost for a lab-scale facility taking advantage of 3D printing technology. Encouraging preliminary results were obtained in an aerodynamic database of the turbine. In particular, the total-to-static efficiency under stationary conditions (i.e. at constant flow coefficients) reached remarkable high values. Hence, the performance curve of the turbine under such stationary conditions has been used to make an assessment of its non-stationary performance in order to compare this optimized radial turbine with respect to impulse axial types available in the literature. The results revealed that radial turbines are clearly competitive against to axial ones when introduced in a twin-turbine configuration for OWC power plants. (C) 2019 Elsevier Ltd. All rights reserved.