The study of similarities between the myths of different cultures leads researchers to uncover common mythological structures, which are repeatedly found in diverse literary and artistic works. "The Hero's Journey" is one of the theories that can be used to identify and analyze these recurring structures in the epic stories of various cultures. The concepts of journey and trial are key elements in myths and are integral parts of legendary and epic tales. Therefore, in comparing different stories, examining the "concept of journey and types of trials" in them becomes crucial. Mythical heroes, in their trials, undergo a "journey" through numerous stages, and many common features emerge during these stages, such as numbers, mythical creatures, and passage through the underworld. After overcoming each obstacle and passing through dangerous places, such as the underworld, the hero concludes their journey after several days or years. The central theme of both the Epic of Gilgamesh and The Seven stages of Esfandyar is also "the journey." This paper, based on Joseph Campbell's approach, examines the journeys of Gilgamesh and Esfandyar, highlighting the similarities and differences between these two important mythological figures in terms of their life periods, reasons for the journey, character traits, type of journey, and more. The findings suggest that these two mythic heroes, while sometimes appearing similar in terms of outward features and narrative structure, differ in their inner characteristics, motivations, and the spiritual essence of their journeys.