Upvote:4
There seems to be at least a couple!
Chuko Awamori in Tomigusuku apparently has free tours.
It's about a twenty minute drive from the airport. I'm not sure if they offer free tasting as the webpage mentions prices for buying awamori, but this doesn't mean there's not also free sipping.
Apparently this is the only company that makes its own earthenware awamori storage jars, which are used for aging.
The company also has its own page about their tours, but it seems to only be in Japanese.
Another seems to be Zuisen in Shuri, not far from the main UNESCO castle in Okinawa. From their website:
Tours of Zuisen Distillery (every 30 minutes from 9:30 to 16:30)
The distillery is an approximately 10-minute walk from Shurijo Castle as well as from Yui-rail Shuri Station.
Feel free to visit us while sightseeing or wandering around the area.
*Reservations are necessary for groups of 10 or more.
I cannot find a central/unified site listing all distilleries, but there are a few pages listing one or two: