Jack Thompson, 24, from Salford, absconded from HMP Kirkham on November 4.
Thompson was sentenced to six years in prison at Minshull Crown Court in July 2017 for offences including robbery and possession of an offensive weapon.
A Lancashire Police spokesman said: “We are keen to find Thompson as soon as possible.
“It is believed he could have travelled to the Greater Manchester area and we would urge anyone who knows where he is to come forward.”
Thompson left the prison with Kyle Meighan, 27, also from Salford, who was later arrested in the Greater Manchester area on December 18.
Meighan had been jailed in January 2017 at Minshull Crown Court for seven years and six months for offences including robbery, burglary and drugs supply.
Thompson is described as white, 5ft 9in tall, of medium build with brown hair and blue eyes.
He has links to the Greater Manchester area and could be violent if approached.