The Boatswain's Mate (BM) Category provides the bulk of Navy’s corps of professional seaman. BMs provide the specialist knowledge, training and supervision of the more advanced seamanship evolutions including anchor work, rope work, small boat handling and operations, berthing, towing, helmsmanship, and replenishment (re-fuelling) at sea. In addition, BM sailors are the Navy’s close range weapon specialists. Maintaining and operating weapons such as the Typhoon and Mini-Typhoon electro-optical remotely fired gun systems, 12.7mm heavy machine gun, Austeyr and Mag 58 submachine guns. The BM is also the Navy's subject matter expert in rifles, pistols, batons and machine guns. Selected BMs also train in demolition charge preparation.

The BM Category also has the primary responsibility for Boarding Operations, and Force Protection. You will specialise in Fast Roping from Navy Helicopters in support of boarding ships. Additionally, within the seamanship area of employment, as a BM you will be able to perform the following tasks: tying knots, rope-work; work with wires, buoys and shackles. You are also required to conduct ships husbandry (Corrosion Control), and evolutions associated with the movement of ships in harbour. Later in your career you may sub-specialise as a Navigator's Yeoman (SE) or Shipborne Lifesaving and Survival Equipment Maintainer (SLSEM).

As a Leading Seaman Boatswains Mate, you have the option of becoming an Officer of the Watch (OOW) on Armidale Class Patrol Boats (ACPB) by obtaining your Limited Navigation Watch keeping Certificate (LNWC). Petty Officer BMs have the ability to increase skill levels by obtaining a Navigation Watch keeping Certificate (NWC).