The 2009–10 season is the Wellington Phoenix's third season of football in the Hyundai A-League, making it the longest running New Zealand team in the competition, surpassing the defunct New Zealand Knights.

Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.

The home kit was changed to a black and yellow vertically striped shirt with black shorts and socks.

The away kit features black sleeves with yellow trim on a white background, while the shorts are white with a yellow and black side trim, with white socks.

Sony renewed its contract with the Wellington Phoenix and remained the club's major sponsor.