Although the crews and staff were mustered by the end of 1943, the unit did not officially form with Avenger IIs as an anti-shipping squadron until 1 Jan 1944 at Squantum in the USA. After a short period of operations over the English Channel prior to D-Day, and about a year in the Far East, the unit left its Avenger IIIs behind, sailed for the UK and disbanded on 8 Dec 1945.
The unit reformed with the Sea King ASaC.7 on 13 Dec 2006 at RNAS Culdrose from 849 Squadron, A Flight.
In May 2009, 854 NAS deployed 3 Sea King ASaC.7 airframes and four crews plus engineering and administrative support to Afghanistan. This was followed by a Nov 2010 deployment to Afghanistan, being relieved by 857 NAS in Mar 2012 and returned to Culdrose. Took part in the security operation for London 2012 Olympics between mid Jul and mid Sep, detaching to RAF Northolt.
Disbanded in Dec 2014 to become Normandy Flight of 849 Squadron.
Locations
| 2006-2010 | EGDR QKZ | RNAS Culdrose |
| 2010-2012 | OAZI |  Camp Shorabak |
| 2012 | EGWU NHT | RAF Northolt |
| 2012-2014 | EGDR QKZ | RNAS Culdrose |
Models
| 2006-2014 | Sea King ASaC.7 |
Operations
| Nov 20102010 | Apr 20122012 | Operation Herrick |
| Jun 20142014 | Jul 20142014 | Operation Herrick |