UNLOCK is the 26th single released by the Japanese idol group KAT-TUN.
"UNLOCK" is the twenty-sixth single by KAT-TUN and the last one released before they entered the temporary hiatus period.
The Limited Edition 1 includes the song "Unlock", the B-side song titled "Ame ni Saku Ai, Yoru ni Naku Ai" and the promotional video and making of "Unlock".
The coupling song "Greatest Journey" was the theme song for KAT-TUN's variety show in TBS titled "KAT-TUN Sekaiichi Tame ni Naru Tabi.
This feat makes "UNLOCK" as the 26th consecutive number-one single that KAT-TUN has released ever since their CD debut in 2006, placing the group in second place after KinKi Kids record of 35 consecutive number one singles.