Deep in the mountains of Japan, we discovered Koyasan, a mystical place where ancient traditions are still alive. Known as a UNESCO World Heritage site, Koyasan is the heart of Shingon Buddhism and home to over 100 historic temples offering unique temple lodging experiences. We spent two nights at Fukuchi-in Koyasan, one of the most beautiful Koyasan temple stays, where we experienced shojin ryori, the traditional vegetarian cuisine of monks, and relaxed in a serene onsen. At night, we walked through Okunoin Cemetery, Japan's most sacred resting place, where the legendary Kobo Daishi is believed to be in eternal meditation. In the morning, we attended a powerful Buddhist ceremony, before setting off on a Koyasan hike along a section of the ancient pilgrimage trails that have guided monks for centuries. From exploring Koyasan Saizenin and other historic temples to discovering a hidden sushi spot in the mountains, this trip was full of surprises! Whether you're looking for a Koyasan day trip or planning a Koyasan overnight stay at a shukubo like Ekoin or Fukuchi-in, this guide will show you the best things to do in Koyasan. Thinking of visiting Koyasan in winter or summer? This magical destination offers something special in every season. And if you're wondering about day trips from Osaka or Kyoto, Koyasan is one of the most unique experiences you can have in Japan!