Coady announced in a statement she is seeking the Liberal nomination of St. John's West.
That seat is currently held by Service NL Minister Dan Crummell.
Coady announced two weeks ago that she would not be seeking the Liberal nomination in the federal riding of St. John's South-Mount Pearl. She held that riding for three years, until New Democrat Ryan Cleary defeated her in the 2011 election.
Coady criticized the direction of the governing Progressive Conservatives.
"We need to focus on education, innovation and excellence in infrastructure, affordable housing, and health. We need good economic managers especially in light of the recent Auditor General’s report," she said.
With the PC leadership race kicking into gear, speculation is mounting about an early election. The leader that the PCs elect will have 12 months to call an election after being sworn in.
Although Coady has not yet won the nomination, her statement quotes Liberal Dwight Ball as congratulating her for entering the race.
"I am very pleased to have someone of Siobhan's reputation and character seek the Liberal nomination," the statement said.
CBC provincial affairs reporter David Cochrane said he understands that George Joyce, who represented the Liberals in the district in the last election, will seek the nomination also. Joyce placed third, behind Crummell and the NDP's Christopher Pickard.