The calculated distance (air line) between Romanshorn and Zürich (Kreis 11) is approximately 41 miles respectively 66 kilometers.
By car or train, the actual journey to Zürich (Kreis 11) is certainly longer, as only the direct route (as the crow flies) between Romanshorn and Zürich (Kreis 11) has been calculated here.
Air line (approximately)
66 kilometers
36 nautical miles