You can freeze raw oysters if they are still alive and in the shell. To ensure food safety and flavor, consume the oysters within three months after freezing them.
The Cold Freeze
Clean the oyster shells and, if you have plenty of freezer space, place them in bags that are resistant to moisture and vapors, advises the National Center for Home Food Preservation. If you need to conserve freezer space, shuck the live oysters and freeze them after removing sand, shell fragments and dirt. Preserve the original liquid in the shells and freeze it in the bags with the oysters.
Leave up to an inch of space for expansion and seal properly, removing any excess air. Freeze rapidly at a temperature of 0 degrees Fahrenheit or lower.
The texture and flavor of oysters is typically altered when they are frozen. So prepare the oysters in soups and seafood stews. Never refreeze oysters.