An internal combustion engine includes cylinders, a cylinder head that includes a pair of intake ports and a pair of exhaust ports for each of the cylinders, and a cylinder block that includes a block-side coolant passage. One of the pair of intake ports and the pair of exhaust ports is a pair of specified ports. The cylinder head includes an inter-port coolant passage between the specified ports. The inter-port coolant passage is connected to the block-side coolant passage through a communication portion. A flow direction is a direction in which the coolant flows in a portion of the block-side coolant passage that is connected to the communication portion. A center of a passage cross section of the communication portion is shifted to a downstream side in the flow direction with respect to a center of a passage cross section of the inter-port coolant passage.