Who can see my location

The short answer, and the exact rule underneath it.

Only people in a space with you, and only while you are sharing.

The precise rule

Your location is readable by someone if, and only if, they share at least one space with you. Not friends-of-friends, not people in your other spaces, and not Circl staff going about ordinary work.

If you leave a space, the people in it lose access immediately.

Visibility is symmetrical

There is no way to see someone without them being able to see you, and no way to appear to be sharing while you are not. If you stop, your space sees that you have stopped.

What staff can see

Administrators can see account details, your name, username and the email on your account, for support and safety. Circl's internal user directory is built so that it cannot show staff your location, your spaces or your activity; those fields are withheld before the data ever leaves the server.