If interested in prisons this is a "must do" trip when in Cape Town, however the sea can have heavy swells and the 30 - 40 minute ride might be uncomfortable for some.  The visitor centre in the Cape Town Waterfront is not only full of historical information but will also direct you to the Robben Island ferries without fuss.

When on the island all tours are guided by ex-prisoners so a first hand account is guaranteed. Don't forget to look out for penguins while you stroll about on this thought provoking location, perhaps an older version of Guantanamo Bay ?