The objective of this work is to evaluate through computational simulation the structural integrity of a horizontal axis hydrokinetic turbine (HAHKT) when using various geometric configurations of diffusers. This study was carried out by fluid-structure interaction (FSI) sing Ansys Workbench V18.2, coupling CFX and mechanical structural, in which a structural analysis was carried out based on the results obtained at the hydrodynamic level of a HAHKT composed of three blades with profile NREL S822, which was also analysed under the implementation of two geometric diffuser configurations. The maximum stresses in the blades increase of 27 % using the third-generation diffuser. © 2024, Semarak Ilmu Publishing. All rights reserved.