The Second Sea Lord and Deputy Chief of Naval Staff is deputy to the First Sea Lord and the second highest-ranking officer to currently serve in the Royal Navy and is responsible for personnel and naval shore establishments. Originally titled Second Naval Lord in 1830, the post was restyled Second Sea Lord in 1904. They are based at Navy Command, Headquarters.

The First Sea Lord and Chief of the Naval Staff (1SL/CNS) is a statutory position in the British Armed Forces usually held by a four star admiral. As the highest-ranking officer to serve in the Royal Navy, the chief is the principal military advisor on matters pertaining to the navy and a deputy to the Secretary of State for Defence. In a separate capacity, the CNS is a member of the Chiefs of Staff Committee and, thereby, a military advisor to the National Security Council, the prime minister and the monarch. The First Sea Lord is typically the highest-ranking officer on active duty of the Royal Navy unless the Chief of the Defence Staff is a naval officer. Admiral Ben Key was appointed First Sea Lord in November 2021.