Alcatraz Island is well-known for the penitentiary that used to be located on the 12 acres of island located a mere 1.5miles/2.5km northeast of San Francisco Bay. Before it was a penitentiary, Alcatraz was named Isla de los Alcatraces (Island of the Pelicans), since Ayala, the first Spaniard to alight, found large numbers of nesting pelicans there.

A lighthouse was erected in 1853 when many ships visited the island, often shrouded in fog, during the California gold-rush. The island was a military prison from 1861-65 during the Civil War, and was used for the well-known jail between 1933-1963.
It is worth paying extra to use the audio tour, which is available in a number of languages. It is advisable to book tickets at least two days in advance, and two to four weeks in advance from May and September.
The ferry trip to Alcatraz Island takes about 15 minutes each way. The only tour to take is Alcatraz Cruises. Other companies do not have permission to stop at the island and allow passengers off their boats. Allocate around four hours for this trip, including the ferry rides.
Smoking, drinks and food are only allowed at the dock, where tourists may make use of the picnic area provided. There is no food service available on Alcatraz Island, so tourists are well-advised to take their own. Dress warmly, since the island has strong winds, and is often covered in mist.
How do you get to Alcatraz Island?
The only way to get to Alcatraz is by a ferry operated by Alcatraz City Cruises, LLC. They are located on The Embarcadero near the intersection of Bay Street – just a bit south east of Fisherman’s Wharf.
Operating Hours & Seasons
The hours of operation vary with the season. Departures are available about every half hour throughout the day beginning at 8:45am. Evening tours, Behind the Scenes Tours, and combined Angel Island-Alcatraz Island tours are also available on a set schedule.
Alcatraz is open every day except Christmas, Thanksgiving and New Year’s day. Alcatraz frequently sells out in advance, as much as a month or more in summer and near holidays. For schedules, prices, and to purchase tickets in advance please visit the Alcatraz City Cruises website.
Source: https://www.nps.gov