[1] For surface running, the boats were powered by two 500-brake-horsepower (373 kW) diesel engines, each driving one propeller shaft.

[4] While on workups in the Hayase Seto off Kure on 15 February 1943, her rudder jammed and she ran aground and suffered hull damage.

[4] She put to sea to begin her second war patrol on 27 May 1943, but diesel engine trouble forced her to return to Rabaul on 29 May 1943.

[4] On 18 July 1943, she torpedoed the United States Navy tank landing ship USS LST-342 in the Blanche Channel off New Georgia at 09°03′S 158°11′E / 9.050°S 158.183°E / -9.050; 158.183 (LST-342).

[4] Rather than return to Rabaul, she received orders on 9 October 1943 to operate off Lae, New Guinea, conducting her seventh war patrol.

[4] She suffered serious damage in the depth-charge attacks the Allied ships conducted against her, and after calling at Rabaul from 23 to 27 October 1943 she proceeded to Sasebo, which she reached on 8 November 1943 to undergo repairs.

[4] On 19 February 1944, Ro-106 was reassigned to the 1st Advance Submarine Unit and set out from Rabaul for her eighth war patrol, ordered to operate within a 90-nautical-mile (170 km; 100 mi) radius of Natsushima at Truk[4] to intercept U.S. Navy Task Force 58, which had made a major air and surface attack against Truk on 17–18 February 1944 in Operation Hailstone.

[4] She returned to Truk on 8 March 1944, the day on which Truk-based Mitsubishi G4M (Allied reporting name "Betty") bombers of the 705th Naval Air Group raided the anchorage at Eniwetok to attack the ships she had sighted.

[4][5] The picket line was tasked with providing warning of any move toward the Palau Islands by Allied invasion forces.

[4][6] After England sank I-16 on 19 May 1944,[6] the hunter-killer group turned its attention to Scouting Line NA.

[4] While George and Raby closed the range, England steamed northeast to cut off Ro-106′s escape.

[4] She crash-dived and began radical maneuvers to disrupt and confuse the sonars aboard the destroyer escorts and avoid hits by their antisubmarine weapons.

[4] George achieved sonar contact on her at 04:10 and fired a barrage of Hedgehog projectiles, but missed.

[4] England made her second Hedgehog attack at 05:01, resulting in three underwater explosions at a depth for 275 feet (84 m).

[7][11] On 15 June 1944, the Imperial Japanese Navy declared Ro-106 to be presumed lost north of the Admiralty Islands with all 49 men on board.