Yes, Onomichi has a bar scene! If you've already had dinner and want a place to just to sit and drink try some of these interesting bars in town:
1. Cat Ch.22
This quiet seaside town had a small red light district in the past, but it is now mostly a bar, snack (bar), and restaurant area at the end of the Hondori (shopping street). Cat Ch.22 has a great selection and one of the few places in Japan I have seen stock absinthe.
2. Beer Bar Cool(?) - (Beer Bar クルー)
There are also a few late night drinking establishments in and around the Hondori itself. This beer bar stocks beers from around the world as well as a few local beers on tap! It is very easy to find with its floor to ceiling glass windows .
3. Rodan (shell bar) - 洋酒喫茶ロダン
Also hidden in the old brothel area is a bar filled with shells and other collected sea life from around the world. The owners live above the bar and have been collecting turtles, sharks, fish, other antiques, and of course many shells for over 50 years. It is more of a museum than a bar, but it is one of the most impressive spots to drink in I have ever seen. They do charge some type of cover charge as is normal in some drinking establishments. (yes, the antiques are spinning on record players)
4. The Restaurant (KOG Bar) @ Onomichi U2
If you're on the North side of Onomichi Station, you might be staying near the Onomichi U2 building. It is a must visit building with a cycling, Onomichi, Shimanami Kaido related souvenir shop, The Restaurant, KOG BAR, and the U2 Hotel. The KOG BAR is a little more upscale than the bar area south of the Hondori and features local ingredients in the food and cocktails.
5. Bar Kato (Bar 加藤)
Kato-san is a very funny guy running an upscale bar. The bar itself is a very expensive piece of wood cut from a tree that spans the entire length of the room. It is a small room, but if you're looking for some Japanese whiskey, scotch, or cognac this would be the place to go.
I have not tried any of the snack bars, but I am sure that there will be a bar or restaurant that will satisfy you in this quaint and beautiful town.