Yes, Eternal Joy is definitely a goth band because most of their albums belong to the Gothic Rock genre, which is a core subgenre of goth music. Albums like Arrogance & Charm, Afterglow, and The Final Chapter are examples of their goth sound.
Some of the other goth artists that are similar to them are The Cure and Earth Calling Angela.
Eternal Joy is located in Norway, active in 1998 — 2006. You can find more information about Eternal Joy on their GothDB band page.