Yes, The Lion, The Witch and The Wardrobe can be considered an isekai, although it doesn’t strictly fit the typical mold of the genre as seen in modern anime and manga.
Isekai, which translates to ‘another world’, typically involves a character being transported from their ordinary world to a fantastical realm. In C.S. Lewis’s classic tale, the four Pevensie siblings discover the magical land of Narnia through a wardrobe. This journey from the mundane reality of wartime England to the enchanted realm filled with talking animals, witches, and mythical creatures showcases a fundamental aspect of isekai storytelling.
However, unlike many contemporary isekai that often feature a protagonist who gains special powers or retains knowledge from their previous life, the Pevensie children are ordinary kids thrust into extraordinary circumstances. They engage with the world of Narnia, facing challenges and adventures that ultimately lead to their growth and development.
In summary, while The Lion, The Witch and The Wardrobe shares core themes of isekai, such as travel to a parallel world and interaction with its inhabitants, it presents these elements in a unique way that distinguishes it from modern interpretations of the genre.