Ben was last seen leaving Carbon nightclub on Eglington Street in Galway city, at around 1.45am on Thursday night.
Ben is described as being 6ft tall, of athletic build, with short brown hair. He was wearing dark jeans and a light blue, round-neck jumper when last seen.
Members of the public are assisting in the search today, which is concentrating on the Oranmore coastline.
Anyone who has seen Mr Garrett or who can assist in locating him is asked to contact Galway Garda Station at 091 538000, the Garda Confidential Telephone line 1800 666 111 or any garda station.