"Love to Say Dada" (also known as "I Love to Say Da Da", "Da Da", and "All Day") is an unfinished song that was written by American musician Brian Wilson for the Beach Boys' Smile project. It referenced the drug LSD in its initials and was one of the last tracks recorded for the album. The song subsequently evolved into "Cool, Cool Water" from Sunflower (1970).
In 2003, Wilson rewrote "Love to Say Dada" as "In Blue Hawaii" with new lyrics by Van Dyke Parks for Brian Wilson Presents Smile (2004). The Beach Boys' original recording of "Love to Say Dada" was released on the compilations Good Vibrations: Thirty Years of the Beach Boys (1993) and The Smile Sessions (2011). The latter release mixed elements from "Cool, Cool Water" into the track.