There are five major oyster species—Crassostrea gigas, Crassostrea sikamea, Crassostrea virginicas, Ostrea edulis and Ostrea lurida.
To put it in simpler terms, they are Pacific oysters, Kumamoto oysters, Atlantic oysters, European flats and Olympia oysters.
Pacific (or Japanese) oysters tend to be meatier and creamier. Some popular types include Kusshi and Marin Miyagi.
Kumamto oysters are more deeply cupped with smaller meats inside. However, these meats are usually a lot sweeter and easier to consume, even for beginners. It is also known as the ‘Chardonnay of oysters’.
Atlantic oysters are usually a lot bigger and they are most commonly found in North America. Their taste come with a slight metallic finish.
Native to Europe, as per its apt name, the European Flat oyster is usually large and quite rare compared to other commercial types. They have their own unique taste that differs greatly from the rest—rich and extremely flavourful.
The Olympia oysters are tiny and are almost extinct right now, hence it is the least common type of oyster found in this day and age.