The 2009–10 Adelaide United FC season was the club's fifth A-League season. It includes the A-League 2009-10 season as well as any other competitions of the 2009–10 football (soccer) season. After a stellar season in the A-League and internationally, Adelaide United began its pre-season without a financial owner; Nick Bianco relinquished his A-League licence back to Football Federation Australia (FFA). Regardless of this situation, the FFA ensured that Adelaide would have the funds available to recruit in the off-season and to maintain the club, whilst they would negotiate the new ownership deals. Adelaide United managed to secure major sponsors Modern Solar as well as Jim's Plumbing for their 2009–10 season.