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.

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30 January 2015 Last updated at 11:48 GMT
But visitors to Niagara Falls in North America got a shock when they saw adventurer Will Gadd climbing UP a frozen section.
Niagara Falls is actually a collection of three waterfalls - he made it up an icy part of Horseshoe Falls, the biggest one.
Will said: "I've been ice climbing for 30 years now and this is the coolest thing I've ever done."
Watch Hayley's clip to see Will in action.

The women, who famously appeared semi-nude in a charity calendar that inspired a hit film, joined Camilla at Buckingham Palace.
They were joined by thousands of Women's Institute (WI) members, at least one from every branch.
The duchess is a member of the Tetbury WI near her Highgrove home.
She was joined at the party by three other royals, the Countess of Wessex, the Duchess of Gloucester and the Queen's cousin Princess Alexandra.
Members of the Rylstone and District WI in North Yorkshire created the infamous calendar in 1999 to raise money after one of their husbands - John Baker - was diagnosed with non-Hodgkin lymphoma and later died from the illness.
Their story was immortalised in the hit movie Calendar Girls starring Helen Mirren and Julie Walters, and now Take That front man Gary Barlow is working on a musical based on their experiences.
Mr Baker's widow Angela, 69, who has since remarried, was one of six of the original Calendar Girls invited to the palace. She was played by Julie Walters in the film, and was the piano-playing Miss February in the calendar.
They all wore their trademark black dresses, string of pearls and a single sunflower - a flower Mr Baker grew before he died.
"It's just brilliant to be here with these ladies, all these fantastic WI ladies," she said.
"When we first did the calendar it was a big thing for me to do, John had just died and we were doing it in his memory and we've raised millions for (the charity) Leukaemia and Lymphoma Research.
"We never thought we would sell so many copies of the calendar, we don't mind people having copied us, but we were the first."
The WI was formed in 1915, a year in to World War One, to rejuvenate rural communities and encourage women to become more involved in producing food to help combat German naval blockades.
It was inspired by an idea from Canada and was first founded in the Anglesey village of Llanfairpwllgwyngyll - famous for having Britain's longest place name.
A memorial has taken place to remember Hull's vessels used in the 1982 Falklands conflict.
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When you think of waterfalls, you tend to picture stuff going down...
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The WI's Calendar Girls have met the Duchess of Cornwall as she hosted a garden party to celebrate the institution's centenary year.