Shannans Pub opened in October of 1976, originally owned and operated by Ben Gillespie and his partner Carl Maglio. Gillespie...from New York , had always dreamed to own an Irish Pub in Puerto Rico and the original location at 1503 Loiza Street was the answer to that dream. Later in the 70's Shannans became the first place in Puerto Rico to have regularly scheduled rock bands playing in a bar on a nightly basis.

At the end of February 1995  (after 19 years) Shannans closed at the orginal location on Loiza Street. That was followed by the opening of the Shannans location in Rio Piedras. Shannans operated in Rio Piedras for eleven years.

On December 29th, 2005 Shannans ceased operations in the Rio Piedras location in preparation for the opening of the current (best and last) location in Guaynabo on February 1st  2006