Yes, a 15-year-old can legally date a 17-year-old in Japan in 2026, but the laws regarding "lewd acts" have recently become more uniform. In June 2023, Japan raised the national age of consent from 13 to 16. This means that sexual activity with anyone under 16 is now a criminal offense nationwide. However, the law includes a "close-in-age" exception: teen couples who are no more than five years apart in age are exempt from prosecution if both partners are over the age of 13. Therefore, a relationship between a 15-year-old and a 17-year-old is legally permissible. Beyond the national law, many prefectures still maintain their own "Youth Protection Ordinances" that can regulate certain behaviors (like late-night outings), so while the relationship itself is legal, parents and guardians still hold significant legal authority over the conduct of minors in such relationships.