The calculated distance (air line) between Siilinjärvi and Seinäjoki is approximately 153 miles respectively 247 kilometers.
By car or train, the actual journey to Seinäjoki is certainly longer, as only the direct route (as the crow flies) between Siilinjärvi and Seinäjoki has been calculated here.
Air line (approximately)
247 kilometers
133 nautical miles