The integration of renewable-based distributed generation (RDG) units instead of conventional fossil fuels is beneficial as it eliminates the negative impacts on the environment while ensuring an efficient operation of the power system. However, because of the irregular characteristics of renewable energy sources (RES), it is essential to ensure the optimum sizing and placement of the RDG units. Several challenges emerge when distributed generation (DG) units are disconnected from the grid, and an islanded system is formed. Ensuring system stability becomes a crucial task in such islanded systems. This paper presents a combined approach to determine the optimal load shedding amount along with the sizing and placement of RDG units by implementing Flood Optimizer. To address this multi-objective optimization (MOO) problem, an objective function is formed that incorporates the voltage stability index (VSI), the total load to be shed, and the overall system losses. The performance of the suggested method was evaluated in an islanding scenario involving two DG units within the IEEE 33 bus distribution system, utilizing MATLAB software. The results were analyzed through simulation, compiling values such as the remaining load on each bus, the size and position of RDG units, VSI, and total system loss