HMS King Alfred is a Royal Naval Reserve shore establishment in Portsmouth, England.

[3][4] In April 2021, it moved to the renovated "Semaphore Tower", within HMNB Portsmouth.

[5] The unit is affiliated with University Royal Naval Unit Solent and Bearwood College Combined Cadet Force and provides local representation at events including the Ship Festival, in Chichester; and the Remembrance Sunday services in Portsmouth and Hove.

[6] Members of the unit are also honorary freedom holders of the City of Portsmouth.

[6] Penny Mordaunt, the local MP and former Secretary of State for Defence, was an acting sub-lieutenant there from 2010 until 2015.