Sushi at Tsukiji Market
Senso-ji Temple
Golden Pavilion
Kiyomizudera Temple
Peace Memorial Park
Miyajima Shrine
Jagalchi Market
Gyeongbokgung Palace
Namsan Tower
Hallasan National Park
Hyeopjae Beach
Seokguram Grotto
Bulguksa Temple
Myeongdong Shopping Street
If you have more time, consider adding a visit to Osaka Castle in Osaka, or Changdeokgung Palace in Seoul. If you have less time, you can skip Jeju Island and Gyeongju, and spend more time exploring Tokyo and Kyoto in Japan, or Seoul and Busan in Korea.