How many volumes of Attack on Titan are there?
The main series is 34 tankōbon volumes, collecting 139 chapters serialized in Bessatsu Shōnen Magazine between September 2009 and April 2021. Volume 1 appeared on 17 March 2010 and volume 34 on 9 June 2021. In English, Kodansha USA published the same 34 volumes between June 2012 and October 2021.
Around that spine sit the extras a collector has to keep straight: a 2006 one-shot prototype, two special editions of volume 34 sold alongside the standard one, limited editions of many middle volumes bundled with anime DVDs and goods, and the spinoff shelf: Before the Fall (17 manga volumes), Junior High (11), No Regrets (2), Lost Girls (2) and Spoof on Titan (2). The full cover run of the main series is in the gallery.