The Dutch Walrus-class submarine HNLMS Dolfijn spent 24 hours in Plymouth on a scheduled port visit to Devonport.
Westward Shipping News captured the submarine yesterday evening on our 24 live webcam.
The submarine plays a vital role in performing intelligence operations, and can reach a top speed of 13 knots when surfaced, and 20 knots when submerged.
Naval experts say the Walrus-class submarine boasts a twin-hull configuration in a teardrop shape that was visible in pictures of the sub leaving the Sound today.
HNLMS Dolfijn is powered by diesel-electric propulsion systems.