HMS Spearhead was a S-class submarine of the third batch built for the Royal Navy during World War II.

[2] For surface running, the boats were powered by two 950-brake-horsepower (708 kW) diesel engines, each driving one propeller shaft.

[1] On the surface, the third batch boats had a range of 7,500 nautical miles (13,900 km; 8,600 mi) at 10 knots (19 km/h; 12 mph) and 120 nmi (220 km; 140 mi) at 3 knots (5.6 km/h; 3.5 mph) submerged.

[1] HMS Spearhead was laid down at Cammell Laird's Birkenhead shipyard on 18 August 1943, was launched on 2 October 1944 and completed on 21 December 1944.

[5] Spearhead survived the Second World War and was sold to the Portuguese in August 1948 and renamed NRP Neptuno.