Castle St is the fourth studio album by New Zealand band Six60. The band's second collaboration with American music producer Malay, Castle St debuted at number one on the New Zealand Albums Chart.

The album was co-produced by American music producer Malay, who previously worked on the band's 2019 album Six60.

The album's title comes from the Dunedin Street where the band members lived during university.^[1] The band began working on the album in Los Angeles, where they spent six months together. Band vocalist Matiu Walters felt that this time was a period of rejuvenation for the band, where they rediscovered the bonds they had created when originally living together as flatmates.^[2]

The album's first single "Before You Leave", inspired by the birth of lead vocalist Matiu Walters's daughter, was released on 19 August 2022.^[2] This was followed by "Never Been Tonight" in September 2022, which featured the album track "Nobody Knows" as the single's B-side.^[3]

To promote the album, a replica of their Castle Street house was constructed and displayed in Eden Park, Auckland.^[1]

The band toured New Zealand during the summer between October 2022 and March 2023, with their annual Six60 Saturdays tour.^[2] The band's previous summer tour was postponed due to the effects of COVID-19 in New Zealand.^[2] New Zealand band Supergroove reformed to play as an opening act for the tour's Wellington and Auckland dates.^[2] The band also toured Australia with The Castle St World Tour, held from December 2022 to February 2023.^[4][5]

• Trey Campbell – songwriting (8)
• Ji Fraser – guitar, songwriting (1–10)
• Marlon Gerbes – keyboards, songwriting
• David Kutch – mastering engineer
• Raul Lopez – engineer, mixer
• Chris Mac – bass, songwriting (1–10)
• Malay – producer, songwriting
• Eli Paewai – drums, songwriting (1–10)
• Paul Phamous – songwriting (11)
• Matiu Walters – vocals, songwriting
• Simon Wilcox – songwriting (1–7, 9–10)
• Yelawolf – songwriting (2)