It is possible to freeze water chestnuts. If they have been peeled and cooked before freezing, their shelf life is as long as a year, but unpeeled and raw chestnuts only last about six months in the freezer.
It is important to freeze water chestnuts in containers that resist vapor and moisture and that are not fragile at extremely low temperatures. Hard plastic or glass containers, heavy-duty aluminum foil and freezer-grade plastic bags all work well with water chestnuts.
When using frozen water chestnuts, those that were frozen raw require thawing at room temperature, while those that were cooked before freezing may go directly into dishes that are under preparation without thawing.