The submarines were decommissioned at Devonport Naval Base in Plymouth, where the crews of both the submarines conducted the final parade.
The parade was witnessed by HMS Talent patron Princess Anne along with other officials and guests.
Trenchant completed its operational career last year, while Talent conducted the last patrol in spring this year.
The Trafalgar-class submarines served the RN for over three decades. The boats were primarily involved in conducting maritime target detection, tracking and classification.
The submarines are equipped with Spearfish torpedoes and Tomahawk cruise missiles.
HMS Talent last commanding officer lieutenant commander David Fox said: “Numerous port visits, exercises, memories and stories are all interwoven into the rich and inspiring history of a submarine which has maintained a steady vigil on the forefront of the defence of the UK and indeed, the world.
“The dedication, fortitude and commitment shown by the ship’s company over the years is commendable and Talent will be sorely missed now her Ensign has been lowered for the last time.”
The RN has decommissioned all the Trafalgar-class submarines, except HMS Triumph. The old fleet is being replaced by the new fleet of seven Astute-class submarines.
Besides, the RN has already commissioned four of seven Astute-class submarines.
Earlier in February, the fifth Astute-class submarine, HMS Anson, completed its initial trim dive checks.