Propelled on the surface by two diesel engines producing a combined 6,000 horsepower (4,474 kW), they had a maximum speed of 18.6 knots (34.4 km/h; 21.4 mph).

When submerged, their two electric motors produced a combined 2,250 horsepower (1,678 kW) and allowed them to reach 10 knots (19 km/h; 12 mph).

Also called "deep-cruising submarines", their range on the surface was 10,000 nautical miles (19,000 km; 12,000 mi) at 10 knots (19 km/h; 12 mph).

Laid down at Ateliers et Chantiers de la Loire in Saint-Nazaire, France, on 20 July 1927[2] with the hull number Q149, Actéon was launched on 10 April 1929.

[2] At the start of World War II in September 1939, Actéon was assigned to the 3rd Submarine Division based at Toulon, France.

[7] By 1 January 1942, Actéon had been reassigned to Casablanca, where she formed the 5th Submarine Division with her sister ships Fresnel, Henri Poincaré, and Pascal.

[7] The submarines of the 5th Submarine Division received orders to proceed to Toulon on 8 November 1942 to undergo a major overhaul, but Actéon and Pascal were still in French North Africa at Oran in Algeria that day when Allied forces landed on the coast of North Africa in Operation Torch.

[7] As she approached the carriers on the surface, the British destroyer HMS Westcott sighted her at 21:00 at a range of 900 metres (980 yd).