Yes, Subtonix is definitely a goth band because most of their albums belong to the Deathrock genre, which is a core subgenre of goth music. Albums like Tarantism, Demo, and Rip Your Heart Out! are examples of their goth sound.
Subtonix is located in United States, California, San Francisco, active in 1997 — 2002. You can find more information about Subtonix on their GothDB band page.
Want to check if another band is goth? Search other bands.