The calculated distance (air line) between Tuen Mun San Hui and Sham Shui Po is approximately 13 miles respectively 20 kilometers.
By car or train, the actual journey to Sham Shui Po is certainly longer, as only the direct route (as the crow flies) between Tuen Mun San Hui and Sham Shui Po has been calculated here.
Air line (approximately)
20 kilometers
11 nautical miles