The Swans will pay £300,000 to the Robins in return for the services of the Irishman.
He will sign a two-and-a-half year deal subject to passing a medical at the Liberty Stadium.
A spokesman said: "We've agreed a fee with Swindon worth £300,000 and he's agreed personal terms.
"He's undergoing a medical and we are expecting to make an announcement in the next 24 hours.
"Hopefully he'll come into the reckoning for Saturday's game at Bristol City."