The 35-year old Australian defender has joined the J.League outfit following his short spell with Sydney FC and is looking to get some regular game time in the lead-up to next year's World Cup in Brazil.
"I am delighted to have reached an agreement with Omiya Ardija," Neill said in a statement released by his agency Inspire Sports Management.
"The J.League is a strong competition as we have seen from the results of the Japanese national team.
"I have been working to a specific strategy in the lead up to next year's World Cup and this represents the next step. I am proud to have joined the club and look forward to doing my best for both my new club and as always my country."
Neill kicked off his professional career with Millwall in 1995 before spending the next decade-and-a-half in England with Blackburn Rovers, West Ham United and Everton. He then joined Turkish giants Galatasaray in 2010 and has since played for Al Jazira, Al Wasl and Sydney.