The Duke and Duchess of Edinburgh have sailed through the harbour in Malta before throwing a wreath and posy into the sea to commemorate British and Maltese lives lost during the Second World War.

On the second day of their trip to the island nation, Edward and Sophie boarded a military ship and sailed through Valletta harbour, where they were treated to dramatic views of the capital’s yellow limestone buildings.

Accompanied by the armed forces of Malta, the duke threw a wreath and the duchess a posy of flowers into the water before a gun salute sounded from one of the city’s high points.

Earlier in the morning, Edward and Sophie opened a new monument to submariners who lost their lives in the Second World War – the Submariners’ Walkway.

The duke unveiled a plaque and then untied a ribbon to open the walkway, prompting applause from a group gathered nearby which included descendants of the submariners who fought in the conflict.

Speaking to them, Edward said: “It’s great to have that recognition now of the service.”

Three British submarines were especially commemorated – HMS Olympus, HMS Urge and HMS Upholder – the first two of which sank off the coast of Malta in 1942.

The duke and duchess then visited the National War Museum, where they viewed a plaque marking the site where the late Queen Elizabeth II – then the Duchess of Edinburgh – “took the salute of the Mediterranean fleet before entering the harbour” in 1950.

The late Prince Philip, Duke of Edinburgh, was with the fleet as first lieutenant in HMS Chequers, according to the plaque.

Sophie touched the words “Duchess of Edinburgh” on the stone, and said it was “very special” to see.

After the boat journey, the duke and duchess walked to the Maritime Museum, saying hello to members of the public as they strolled past – many taking their phones out to snap photos and videos of the royal pair.

Once at the museum, Edward and Sophie spent a few moments on a balcony overlooking the harbour before entering a reception attended by armed forces personnel and members of the Maltese-UK Veterans’ Association.

The duke later met young people taking part in the Duke of Edinburgh International Award.

He was greeted by two teenagers who had some welcoming remarks for him, and ended up comforting one of them who was nervous.

Later, once she had finished her short speech, Edward gave her a hug after telling her she had done brilliantly.

He went on to meet different groups of young people doing different activities, including a group of girls playing basketball on a makeshift court.

One of them asked if he would try shooting, but the duke declined, saying: “If there’s one sport I’m completely and totally useless at, it’s basketball,” before asking if anyone would take the shot for him.

After one volunteer sunk the ball twice, Edward clapped and told her: “You’re definitely on my team.”

At a reception with supporters of the award, the duke made a short speech in which he urged them to meet the youngsters downstairs and “make their day”.

He said: “It’s brilliant that you’re all here and you’re all upstairs… but what’s really going on, and the people that you really need to go meet, are downstairs, and those are all the young people who have come from all over the island today to share their passion in the award and what they’re doing and how they’re doing.

“That is the magic, and that’s what this is all about. So I really … urge you to go downstairs and meet those young people and really make their day.”

Invited to unveil a plaque commemorating his visit, Edward joked to those gathered: “I should just warn you at this stage that the unveiling of a plaque is not necessarily the most exciting thing that has happened in your life, so I just need you to pretend.”