Direct proof of use
The Sea King was used by U.S., NATO, and Afghan-government-aligned forces in the 2001 War in Afghanistan through British Commando Helicopter Force operations. The UK Ministry of Defence reported that Royal Navy Commando Sea King Mk4 helicopters completed their final mission for Joint Helicopter Force Afghanistan in 2011 after deploying with 845 and 846 Naval Air Squadrons in support of Operation Herrick since 2007.
The same MOD account placed the aircraft at Camp Bastion in Helmand Province and described the Sea Kings' Afghanistan work as battlefield transport and support: more than 3,800 missions, about 12,500 flying hours, over 80,000 personnel moved, more than 700 tonnes of ammunition, water, and supplies delivered, plus missions that included casualty extraction, sniper-team insertion, and lifting troops and supplies into enemy-held areas.
Sources: Navy Sea Kings Complete Afghanistan Mission
Timeline
Royal Navy squadron history records 846 Naval Air Squadron deploying to Afghanistan in 2007 with upgraded Sea King Mk4+ helicopters for Operation Herrick, operating throughout Helmand Province alongside 845 Naval Air Squadron.
A 2008 National Army Museum collection record shows a Royal Navy Sea King of Joint Helicopter Force Afghanistan refuelling at Camp Bastion. In 2010, a U.S. Marine Corps exchange pilot was documented flying Mk4 Sea Kings with 846 Naval Air Squadron at Camp Bastion, illustrating the coalition context of the British helicopter detachment. The final MOD release in October 2011 recorded the withdrawal of the Commando Sea Kings from Camp Bastion.
Sources: 846 Naval Air Squadron, National Army Museum Sea King Camp Bastion, US Marine Major Flies with Royal Navy Forces, Navy Sea Kings Complete Afghanistan Mission
Narrative
In Afghanistan, the Sea King was a manned medium-lift and support helicopter, not a strike aircraft or a transferred Afghan platform. The documented operator was the Royal Navy's Commando Helicopter Force, flying within Joint Helicopter Force Afghanistan from Camp Bastion for Operation Herrick.
The aircraft's supported role was mobility and logistics under Afghan-theater conditions. Official and museum sources place Sea King Mk4 aircraft in Helmand and at Camp Bastion, where they moved coalition personnel, delivered supplies, and supported medical evacuation and other battlefield movements. The MOD noted that the Commando Sea King was not designed around Afghanistan's heat and altitude but nevertheless completed its assigned support missions before withdrawal and conversion of the force toward Merlin helicopters.
Sources: Navy Sea Kings Complete Afghanistan Mission, 846 Naval Air Squadron, Wikimedia MOD Sea King Afghanistan Image, National Army Museum Sea King Camp Bastion