Heat transfer in engineering applications has shown progress, especially in electronic devices that raise the need for better heat sink designs. In addition, the generation of heat in devices and electronic circuits has also augmented, leading to the problem of heat dissipation. This study investigates the thermal and fluid flow characteristics of different geometrical configurations of pin fin heat sink under natural convection. The heat sink models studied are Hybrid Pin Fin with Connector Heat Sink (HPFWC HS) and Pin Fin with Connector Heat Sink (PFWC HS). All heat sinks models were simulated using CFD Ansys to analyse each heat sink’s thermal performances and flow fields. The results show that adding wings to the HPFWC HS significantly increased heat dissipation. In terms of heat transfer characteristics, the HPFWC HS has about a 5.78% increase in Nusselt number compared with HPFWC HS. The reason is that the heat sink HPFWC HS has wings around it, and these wings help to promote vortex formation around the fins, which leads to a higher heat transfer coefficient. A fin spacing of 15mm is the best spacing for the heat sink compared to other fin spacing.