Oysters that are still in the shells should only be frozen live. A live oyster will keep its shell tightly closed or will close it when tapped. If you have plenty of freezer space and want to freeze the oysters in the shells, simply wash the shells thoroughly and place in moisture-vapor resistant bags.
To save freezer space, wash the oyster shells, discarding any oysters that have died. Shuck oysters into a strainer (save the liquor) and remove any pieces of shell or sand. If necessary, the oysters can be rinsed to remove any sand. Place oysters and liquor in a plastic container or freezer bag, leaving ½-inch headspace, seal and freeze. Shucked oysters can also be frozen by this method.
Freezing does change the texture and flavor of oysters. These oysters may be best used in casseroles or stews.
This document was extracted from "So Easy to Preserve", 5th ed. 2006. Bulletin 989, Cooperative Extension Service, The University of Georgia, Athens. Revised by Elizabeth L. Andress. Ph.D. and Judy A. Harrison, Ph.D., Extension Foods Specialists.