almost 3 years ago - Munin - Direct link
... from the Store Page:
Approximately how long will this game be in Early Access?
“For at least one year, but depending on player feedback and the amount of content we choose to put into the final game, it may take longer.”

There is no release date yet.
Make sure to press 'follow' on the Store Page to not miss any news.

More info about Valheim's Development here:
https://steamcommunity.com/app/892970/discussions/0/3105773861179040368/