Yes, you can drink tap water in Japan. Tap water in Japan is safe to drink everywhere and meets some of the highest health and safety standards in the world, regulated by the Ministry of Health, Labour and Welfare. It undergoes rigorous purification processes and regular quality monitoring to ensure it is clean and free from harmful contaminants. While tap water is drinkable even in public places like parks and train stations, it's best to avoid drinking directly from temple fountains or natural sources like rivers without purification. Japan is known for its high-quality tap water, and many people drink it without issues throughout the country.