Modern passenger ships must be safe in event of fire or flooding. On this basis, a set of stringent international Regulations has been issued to improve the intrinsic survival capability of a ship. Indeed, specific SOLAS Regulations, commonly known as "Safe Return to Port", are addressed towards design criteria able to guarantee adequate functionality of the ship when a casualty occurs. The main objective is to permit either a return to port by means of own propulsion system or an orderly evacuation of the persons on board. Since December 2006 IMO introduced the basic concepts on this topic, which has been subjected to continuous evolutions through the introduction of new specific requirements. Nowadays, this matter has become of primary importance even in the early-stage design. Indeed, the new amendments to SOLAS Regulation II-2/13.3.2.7 issued on May 2016 made the evacuation analysis mandatory for both new and existing passenger ships since the early steps in the project. In this paper, the new IMO revised Guidelines have been analyzed, and a case study for the evacuation of a 3600-person cruise ship has been carried out by means of both simplified and advanced methods.