Former Socceroos winger Halloran, 29, has six caps for his country - all of them coming in 2014 - but hasn’t featured since, despite being a commanding A-League figure for the Reds over the past three-and-half years.

He has never given up hope of a recall, and a standout 2022 season in South Korea - which kicks off on February 9 - could make it difficult for coach Graham Arnold to ignore him.

Halloran is slated to join fellow Aussie Connor Chapman, the ex-Melbourne City and Western United midfielder, at the Dragons, who have also won two FA Cups and two League Cups.

His exit confirmed by Reds coach Carl Veart after Saturday's 4-0 win over Wellington, Halloran made 88 appearances for Adelaide, scoring 21 goals across all competitions and picking up two FFA Cups and the Aurelio Vidmar Club Champion award in the 2020/21 season.

FC Seoul will be his fourth overseas club after previous stints with Bundesliga 2 sides Fortuna Düsseldorf and Heidenheim before moving to the J-League with V-Varen Nagasaki in 2018