As PRINCE2 and ISO 21500 (International Organization for Standardization, 2012) have different structures and scopes, it is not always possible to make direct comparisons clause by clause.

• ISO 21500 does not cover, in its processes, the roles of what PRINCE2 refers to as the executive or the team manager. However, PRINCE2 and ISO 21500 do share a core of common practice relating to the role and activities of the project manager.
• ISO 21500 does not define the roles of team manager or team member in any detail because they, like the project sponsor, are outside the standard’s scope.
• In terms of project lifecycle, PRINCE2 and ISO 21500 have the same concept of phases/stages, with decision points where each phase/stage of the project starts. ISO 21500 provides no detail on best practice relating to such decisions, which are deemed out of scope.
• The actual structure of ISO 21500 in its logical form is very different from that of PRINCE2. In PRINCE2, the stages of a project are explicit and defined within the processes, such that the initiating and closing of a project is done in a different way from the initiating and closing of a phase/stage. ISO 21500 treats a project and a phase/stage within a project identically and has no explicit procedure for starting new stages within a project. How this is done is left to the user of the standard to determine. PRINCE2 provides detail on this in its managing a stage boundary and directing a project processes.
• Being a method, PRINCE2 has details of techniques and approaches which are not in ISO 21500 (e.g. product-based planning).

Therefore, if an organization is using PRINCE2, it could be said to comply with ISO 21500 provided that those aspects which are explicitly beyond the scope of PRINCE2 are covered either by its enterprise method or by other corporate processes and methods.

Source: Prince2 Manual