The calculated distance (air line) between Flawil and Zürich (Kreis 9) is approximately 33 miles respectively 53 kilometers.
By car or train, the actual journey to Zürich (Kreis 9) is certainly longer, as only the direct route (as the crow flies) between Flawil and Zürich (Kreis 9) has been calculated here.
Air line (approximately)
53 kilometers
29 nautical miles