Is there anyway to buy tickets for a Alcatraz tour, if they are already sold out?

if you go down to ticket office early,people bring tickets back,its near where you get on the boat

It is a long shot, but keep checking the official tickets site. I think in case of cancellations they sometimes have open slots for tours scheduled for the following 1-3 days. I bought my ticket 2 days before the tour after initially not being able to find anything.

There are some tour groups that buy lots of tickets but the prices tend to be expensive and are bundled with stuff you may or may not want to do. You need to be very careful with tour groups as there are a number of tours that just circle the island, you need to ask if they have a ticket that allows you to step foot on the island.

https://sfbay.craigslist.com is a long shot but it is possible that someone will book a ticket that they cannot attend.

you can buy same day tickets but you have to buy them in person at the pier. i would show up before they even open to make sure you can get a ticket. There are also standby tickets for the night tours http://www.inside-guide-to-san-francisco-tourism.com/alcatraz-tour-tickets.html

Call and ask. Tours opened up on Sunday for this coming Wednesday, and I couldn't believe I got two tickets only a few days beforehand. Call and ask, they have openings that aren't always uploaded onto the site.

It's really not that great.