Studio Two, EMI Studios, Abbey Road
The backing track for Paul McCartney's song Good Day Sunshine was recorded during a 12-hour session which began at 2.30pm.
Upon their arrival in the studio, The Beatles rehearsed Good Day Sunshine for some time before recording began. At this stage the song had the working title A Good Day's Sunshine.
They recorded three takes of the rhythm track, the first of which was chosen as the best. McCartney played piano and Ringo Starr was on drums. Onto track two of the four-track tape McCartney added lead vocals for the verses; track three featured John Lennon and McCartney's vocals in the chorus; and McCartney's bass guitar was overdubbed onto track four.
Source: Beatles Bible