Yet again, I have missed the boat! I will be in San Fran for short time and the dates are already sold out. Does anyone know from experience if I will have any luck just turning up on the day. My preference is for the night tour but will do the day tour anytime. On one of the days, Alcatraz Cruises has the Alcatraz and Angel Island tour which is double price and longer. Has anyone done this tour and would recommend it?

Regarding the sold out tickets, you can try calling the concierge at the hotel you'll be staying. Sometimes they can miraculously get hold of tix...

Yes. Alcatraz Cruises has about 100 tickets that they sell for the day of. Lines have been forming starting at 4:30 or 5 am so get there early. Also, everyone who wants to get one needs to be there in person. Good luck.

You might try to catch a ferry from Larkspur or Sausalito

Ferries from Sausalito and Larkspur do not let people off at Alcatraz (if they stop there at all). There is only one way to get onto Alcatraz Island and that's via the official nps boat.

I work near the Wharf (unfortunately) and recently I have seen touts in front of some of tour operators with signs stating they have Alcatraz tix available that day. I cannot vouch for the accuracy or source of said tix because I never inquire. Anyway it's a possibility.