Rinkai Line
Osaki Station (JR) - 13 minutes - Kokusai Tenjijo Station
Shin-Kiba Station (JR,Subway) - 5 minutes - Kokusai Tenjijo Station
Yurikamome
Shimbashi Station (JR, Subways) - 22 minutes - Kokusai Tenjijo Seimon Station
Toyosu Station (Subway) - 7 minutes - Kokusai Tenjijo Station
Toei Bus
Niji01: Hamamatsucho Station (JR/Monorail) - about 40 minutes - Tokyo Big Sight
Umi01: Monzen-Nakacho Station (Subway) - about 30 minutes - Tokyo Big Sight
Higashi16: Tokyo Station (Yaesu Exit/JR) - about 40 minutes - Tokyo Big Sight
Water Bus
Hinode Pier - 20 minutes - Ariake Terminal
Access information on the Tokyo Big Sight website:
http://www.bigsight.jp/english/general/access/index.html