Prosciutto is ham that undergoes a process called "dry curing." The steps involved in dry curing Prosciutto are exacting and date back to ancient times. The entire process of drying the ham can take from nine to 18 months. It is commonly served thinly sliced, uncooked and is ready to eat when purchased. The unique quality and taste of Prosciutto is said to be partly due to the Italian air and climate. This may be a distinction that helps set it apart from other dry cure hams around the world. There are enough alternatives to choose from when the real thing is not available that all but the most dedicated purist should be satisfied.
A common choice of a substitute for Prosciutto is another uniquely Italian cured meat known as Pancetta. This is actually pork belly meat, which is the equivalent of bacon. Pancetta is not ready to eat like cured ham. It is usually found packaged similar to a sausage and must be sliced and fully cooked.
Regular unsmoked bacon, if thinly sliced, can also provide a substitute for Prosciutto. Canadian bacon is another alternative. Turkey bacon has been popular as a non-pork alternative to regular bacon and might be creatively used in some dishes. Italian Bresaola, slices of spiced and air-dried beef, are an alternative that is also similar in appearance to thin ham or Prosciutto.
You cannot go wrong with many types of ham, which are among Prosciutto's closest relatives. One of the closest substitutes for Prosciutto is Serrano ham, a Spanish dry-cured ham. Westphalian, Black Forest, York and Ardennes ham are all dry-cured "country" hams and make good substitutes for Prosciutto. Virginia ham is another good alternative.
Nutty and flavourful cheeses, sliced thin, have been suggested as possible substitutes for those who wish to avoid meats altogether. These might include varieties of Gouda, Asiago and others. Or, what about a Prosciutto-complimentary flavour like Havarti? The possibilities are as wide as your imagination and the substitutes potentially cover all of what we know as antipasti and much more. Your imagination may lead you to take some risks that taste very good.