coldrain (katakana: コールドレイン) are a Japanese post-hardcore band formed in ~2007 by Masato, Y.K.C, Sugi, RxYxO and Katsuma who are all still active members of the band at the time of writing.

They have released 7 studio albums, the latest of which being OPTIMIZE=OPTDEMISE.

The lead singer, Masato, is half Japanese and half American but he sings almost exclusively in English due to being more comfortable in that language when singing. However, the majority of their fanbase is still in Japan due in no small part to the fact that, until their recent signing with Century Media, they have very scarcely interacted with or distributed merch to their global audience.