The service at Holy Trinity Church was followed by a parade to Victoria Pier to cast wreaths into the Humber.
Keith Thompson, organising the parade, said during the conflict the Royal Navy requisitioned more vessels registered in Hull than from any other British port.
Trawlers, tugs and a North Sea Ferry, Norland, were manned by volunteers.
Argentina invaded the Falkland island in April 1982. About 650 of its troops, 255 British servicemen and three Falklands civilians died in two months of fighting.
The Norland Hull to Rotterdam passenger ferry landed Royal Marines and other forces in San Carlos Water and was often attacked by Argentine forces.
Mr Thompson, a Falklands veteran from the Norland, said in total nine Hull-registered vessels sailed - "the largest Falklands task force from one port".
Later in the conflict, the Norland transported prisoners of war back to Argentina and returned to Hull in 1983. She was scrapped in 2010.
During today's wreath-laying service on the pier, Hull firm SMS Towage was due to pull a tug down the Humber with jets firing as a mark of respect.
Mr Thompson said the public was invited to attend the service and the pier parade to lay flowers "for a loved one lost at sea in war or in peace time".
In the world wars hundreds of Hull trawlers and crews were also requisitioned by the Admiralty and used as minesweepers and patrol craft. Many merchant seamen were killed in action.
The memorial service took place at Holy Trinity, the nearest church to the port.
A memorial has taken place to remember Hull's vessels used in the 1982 Falklands conflict.