Debris of (or from) KRI Nanggala recovered. The following is based on this report.
On April 24, 2021, the Indonesian Navy announced the finding of debris, including a part associated with torpedo tubes, a coolant pipe insulator, a bottle holding periscope grease, and prayer rugs.
Because the debris was found within 10nm of the point of last contact and no other vessels were believed to be in the area, the debris was believed to have come from KRI Nanggala, hence the submarine was declared sunk.
Chief of Staff, Indonesian Navy, Admiral YudoMargono stated that a sonar scan had shown Nanggala at a depth of just under 850m ie. fatally below its crush depth of about 500m.
On 25 April, after a more accurate sonar and magnetometer scan by KRI Rigel (933) (an Indonesian Navy Hydro-Oceanographic Assistance Ship with more powerful sonar equipment) the Indonesian Navy confirmed that all 53 of Nanggala’s crew were lost.
Underwater scans have identified parts of the submarine, including the rudder, external parts of the pressure hull, diving plane, anchor, and other miscellaneous items such as the MK11 submarine escape suit. The remotely operated vehicle (ROV) from Singapore Navy's MV Swift Rescue also made visual contact with the wreck and determined that KRI Nanggala had split into three parts (broken up in fragments). Nanggala is located at a depth of 838m at coordinates 7°48′56″S 114°51′20″E Coordinates: 7°48′56″S 114°51′20″E."