Kumamoto Streetcars
I remember doing some research of Kumamoto and there was a suggestion to use the Streetcars/trams. Official website: Getting Around Kumamoto
Part of my trips to Japan is to experience their transport system as it is one of the best in the world.
After getting out of Kumamoto station, the East exit will bring you to a location to jump on the streetcar (as they are called there). 
There was a flat fee, I think 170 yen, each way (for an adult). I had Suica, so I just tapped when entering and exiting. I didn’t realize that there was an all day pass for 500 Yen.
I would have grabbed that.
From what I gather, you want to enter the back and exit the front (but that depends on which type of street car).
There are 2 lines, A and B, and go to different locations.
I was still trying to figure out how to get to Hanabatacho station (shopping streets). There are a few different trams. I rode a few to get a feel for them going one way and the other (I also jumped on the wrong line on the way back to Kumamoto station).
This one was kinda interesting and was also the one I took. It was really a luxury tram!
This thing was like a diner tram!
A couple of the trams had wood flooring.
Some of the platforms/stops cater to both lines, make sure you get on the right one!
Pretty convenient to use! Either an IC or 1 day pass is good, with the pass being worth it if you are gonna use it for a few stops.