"After consultation with the coaching staff, the Dragons board determined that granting the early release requested by Jamie and his management was in the best interests of both parties," Dragons CEO Peter Doust said in a statement.
"It is fair to say that mid-season signings and transfers are not ideal for clubs, players or fans but that is the system in which we work.
"This is not how the club or Jamie envisaged things would end and efforts were made to avoid this circumstance but both parties agree that this is the best outcome.
"Jamie has made a significant contribution to our club. We thank him for his services and wish him well for his future."
Soward, who was part of the Dragons' side that won the 2010 grand final, said he was grateful to the club for allowing him to take up the offer to play overseas.
"I would like to thank the Dragons and everyone associated with the club for everything that they have done for me throughout my time at the club," said Soward.
"St George Illawarra is a special club with great people and I have some great memories to take with me, especially the grand final win in 2010."
- AAP
