Is PRINCE2 a waterfall method?

PRINCE2 is often described as a waterfall method.  The Waterfall model, briefly, is a step by step approach to software development in which phases follow each other rigidly as night follows day.  It's a structured approach with emphasis on up front work to fully document requirements and design. You can see the parallels with PRINCE2: PRINCE2 is has a rich document set available PRINCE2 is up front.  X of PRINCE2's Y activities are devoted to Starting Up and Initiating the Project It's not called PRojects IN Controlled Environments for nothing - PRINCE2 likes structure But PRINCE2 is not a waterfall model, and never has been.    

Why does the "PRINCE2 waterfall" idea persist?

It's a straw man argument

It's mostly used to justify abandoning PRINCE2 and adopting something else, usually agile.  Agile is good, and great things are being done with approaches like Scrum and Kanban.  But PRINCE2 is strong in areas that agile is weak.  The new PRINCE2 Agile guidance blends together PRINCE2 and agile techniques to give a best of both worlds solution.

Prejudice about PRINCE2

PRINCE2 is hard work.  All projects are, even the good ones.  We mere humans are always looking for an easy solution - so we find ways to dismiss it
  • PRINCE2 puts management and the business in charge.  Software development approaches give developers a stronger position.  The "PRINCE2 waterfall" argument usually comes from the bottom up
  • They haven't read it - and 400 pages looks like a lot of work.  Not reading further is rationalized by recycling the criticisms you just read somewhere else
 

Failure to apply PRINCE2's Tailoring principle.

PRINCE2 is very flexible and can be adjusted to suit the size, scale and complexity of your project.  Experienced PRINCE2 project managers know this & they're relaxed about what can and can't be done.  The short answer to "is this a PRINCE2 project" is "does it follow the 7 PRINCE2 principles."   I always tell my students that there's no such thing as "PRINCE2 compliant."   If you use PRINCE2 in a modified form, and your project is successful, you did the right thing.  You're judged by the result you delivered, not the details of your method.