Starting in 1937 the G3Ms were used in the Sino-Japanese war.
Around the World
From August 26 to October 20, 1939, a L3Y-2 flew 33,000 miles in 194 hours around the world.
By December 1941 there were approximately 250 G3Ms in service. During the first two years of the Pacific War, the G3M was the main medium bomber of the Imperial Japanese Navy.
HMS Repulse and Prince of Wales
The G3M2s played a major part in the sinking, off of Malaya on December 10, 1941, of the HMS Repulse and Prince of Wales.
After 1942 the G3M was primarily relegated to secondary roles such as transport, training, and glider towing. Some had search radar added and were used as long range maritime patrol bombers.