Yes. Options include
- Opening a browser and entering the forum URL
- Using a freeware Discourse app called Discourse Hub. This can be installed and a site, or multiple sites, accessed easily from it. It saves typing when opening the forum.
As expected, the display is responsive to the small screens, so the menu options and other features are arranged a little differently.
The app is available through PlayStore and AppStore.
There is also an Apple app called Fig that looks like it supports Discourse as well as other apps. As I have an Android phone, I have no idea how effective it is.