Kumamoto Station is a primary hub station for Kumamoto Prefecture. Since Kyushu Shinkansen, limited express trains and tourist trains are available at this station, it is popular among tourists.
There is a car rental service office in the multistory parking space located 100m to the left from the Shinkansen Exit. You may rent a car here for Kumamoto sightseeing.
There is easy access via general roads when you go to famous sightseeing spots from Kumamoto Station. Kumamoto Castle is about 10 minutes drive. Aso is about an hour and 15 minutes, Kurokawa Onsen is about an hour and 50 minutes and Kuju and Takachiho are about 2 hours drive. You will be driving along the Five Bridges of Amakusa which is also known as the Amakusa Pearl Line, when you go to Amakusa. You don't want to miss the vast beautiful views from these bridges.