On 7 December 1942 theRoyal Dutch East Indies Navy (Nederlands-Indië Marine) had 15 submarines. The Submarine Flotilla was under the command of Lt.Cdr. A.J. Bussemaker with a headquarters located at Soerabaja Naval Base, Java Island...

The Imperial Japanese Navy (IJN) committed 18 submarines in three squadrons to support the operations in the Southern Area. The Southern Area consisted of the Philippines, Singapore, and the Netherlands East Indies. The three squadrons (or flotillas) sent to the Southern Area were the four minelaying submarines of Submarine Squadron 6 under Rear-Admiral Chimaki Kono, the eight fleet submarines of Submarine Squadron 4 under Rear-Admiral Etuzo Yoshitomi, and the six fleet submarines of Submarine Squadron 5 under Rear-Admiral Tadashige Daigo...

The Japanese Submarine Operations, December 1941-February 1942 by  Dan Muir
The Japanese Submarine War 1941 - 1942 by  Allan Alsleben

The United States Navy's (USN) submarine force assigned to the defense of the Netherlands East Indies (NEI) against Japanese Invasion were part of the USN's Asiatic Fleet based in the Philippines. This submarine force was made up of 28 submarines of which 23 were 'Fleet' subs and 5 were old S-Boats. Soon after the bombing of the USN fleet at Pearl Harbor, Hawaii, on December 7th, 1941, Japanese bombers from Formosa began bombing the Philippines. On December 10th, Japanese bombers struck the Cavite Naval Base in Manila Bay. The submarine tender Otus (AS.20) was straddled by several near misses during the attack but escaped unharmed. However, much of the Cavite Naval Base was a shambles. In addition to suffering over 500 dead in the attack, the submarine repair facilities, torpedo overhaul shop, and over 200 torpedoes were destroyed. These losses were a severe blow to the USN submarines based in the Philippines...

The USN and Royal Navy Submarine Operations, December 1941-March 1942 by  Dan Muir

By mid January 1943 the Anglo-American naval blockade of Germany had reduced, step by step, the stocks of those strategical materials the German were already short of (namely rubber, tungsten, molibdenum, copper, vegetal substances, quinine and some kinds of oils) and which were absolutely necessary to carry on the war. All these goods, uncommon in Europe and whose production was rather difficult, were on the contrary largely available in the Asiatic regions conquered by the Japanese during the war. The Indonesian Archipelago, the large and rich Dutch colony, invaded by the Japanese in the spring of 1942 after a rapid aeronaval offensive, could supply Germany and the Axis countries with the strategical materials they needed on condition that they were able to build ships fit for a voyage out and home on a very long and dangerous course....

In 1939 the Soviet Pacific Fleet, under command of Vize-Admiral Ivan Jumasev, had 14 destroyers, 30 minesweepers, 92 patrol boats and more than 80 submarines. The fleet in 1941 had slightly changed with 2 light cruisers, built recently in that year, each of 8,800 tons, and could do 35 knots, there were also 16 destroyers and now 94 submarines. The submarine fleet had various vessels, thirteen of Type 'L, forty-one of Type 'Shch, thirty-three of Type 'M, six of Type 'S and only one of Type 'K. Of the main Soviet naval base at Vladivostok for the Pacific Ocean it was said that no other Soviet fleet in other seas had such power, which is understandable if we consider the large number of submarines and destroyers. Wartime operational activities and patrols occurred mainly during August 1938 when Japanese Army invaded the Soviet Union near Hasan Lake....