The Kaplan turbine has guide vanes to control the water flow to the runner blades in the turbine, regulate the water flow, and stop the water flow. The objective of this research is to obtain an optimal design of the linkage guide vanes for a 6-blade Kaplan turbine and determine the thrust force values generated by the water flow when the guide vanes are opened at 20%, 40%, 60%, 80%, and 100% from the closed position. The research begins with a preliminary design to determine the forces and minimum dimensions, followed by a 2D and a 3D design, then developed with automatic meshing, boundary conditions, loading, and material properties to get stress simulation. In contrast, flow and pressure simulation is performed on the spiral case when the guide vanes are closed and opened at 20%, 40%, 60%, 80%, and 100%. Validation of the simulation results shows that this linkage guide vane mechanism design can open and close the guide vanes. The minimum safety factor obtained is 4.02, and the maximum pressure is 360393.95 Pa when the guide vanes are opened at 20% from the closed position. The minimum pressure obtained is 118084.31 Pa when the guide vanes are opened at 100%. This design is deemed feasible as it does not exceed the minimum safety factor requirement of 4.