both sides. the Germans and Japanese had subs, so did the Americans and British. the French had some at the beginning of the war, but as it was becoming apparent they would be conquered, they scuttles their fleet, both surface and sub.
World War I submarines were primarily used to locate and attack surface cargo and warships.
Both sides, the Allies and the Axis, had submarines when WW2 started.
submarines were used in WW1 and the weapons used were torpedos and a deck gun.
They were used extensively throughout the war - from beginning to end.
They were used by submarines to navigate when not in open waters, They were also used by submarines and anti-submarine ships to locate enemy submarines.
During World War 2, it is reported that over 2,000 variants of Japanese Submarines were used during World War 2. Out of this, it is estimated that 10,000s were likely to be used during WW2.
Yes, many submarines were used in WW1 by most of the major combatants.
World War 1
Britain, France, Germany, Italy and USA all used submarines during WW1
Why don't you just Google "World War 1 Submarines?"
An estimation of about 600 subs were operated during the war.
No, not really, submarines were first used successfully in the Civil War.