McCartney III was recorded in early 2020 in Sussex, England at McCartney's home while in lockdown amid the COVID-19 pandemic. Describing the process of recording the album, McCartney said: "Each day I’d start recording with the instrument I wrote the song on and then gradually layer it all up; it was a lot of fun. It was about making music for yourself rather than making music that has to do a job. So, I just did stuff I fancied doing. I had no idea this would end up as an album." Like previous McCartney albums, the instrumental work is recorded by McCartney himself. He similarly performed most of the instruments on his 2005 album Chaos and Creation in the Backyard and on his 2007 album Memory Almost Full.