Prince Harry was greeted with cheers as he started his first official visit to Australia.
The prince is representing the Queen at the International Fleet Review in Sydney, which features around 40 warships from 17 countries.
He arrived in the city last night to a warm welcome at the city's Kingsford-Smith Airport at the start of his two-day visit to the country.
This morning he was greeted by a crowd of hundreds as he embarked on survey ship HMAS Leeuwin at the city's Garden Island naval base before inspecting the flotilla.
The prince wore a white British Army tropical dress uniform with the sky blue beret of the Army Air Corps as he took the salute.
Among the crowd were naval trainee medics Ayesha Sweeney, 19, and Renee Simmons, 21, who live six hours' drive away at their base in Aubrey, New South Wales.
Ms Simmons described Harry as "gorgeous", adding: "I'm in love. He wears a uniform very well."
Miss Sweeney added: "It was good to get a royal visit today for the review, it adds that extra excitement to it."
Sydneysider Meagan Roberton, 50, who went to the street outside the base with her family, said: "We didn't expect to see him today so it's an added bonus.
"He's gorgeous, we all love him in Australia. I remember when he was born."
Harry was joined on board by prime minister Tony Abbott and governor general Quentin Bryce, the Queen's representative in Australia.
The review is being held to commemorate 100 years since the Royal Australian Navy's (RAN) first modern warships sailed into Sydney, seen as a defining moment in the country's maritime history.
More than a million people are expected to line the banks of Sydney Harbour today for main day of the review and to catch a glimpse of the prince.
The event will involve 8,000 naval personnel and Royal Australian Air Force aircraft, and will finish with a firework display over Sydney Harbour Bridge.
Britain has sent one of its latest and most advanced ships, Type 45 destroyer HMS Daring, to represent the Royal Navy.
RAN spokesman Commodore Paul Kingshorne said the force was pleased Harry had come to mark the event.
"It is his first official visit here representing the Queen," he said.
"The fact he is here on such a significant day for the navy and for Australia is fantastic for us."
Harry, 29, is one the younger royals being looked at to increasingly take on the more long-haul parts of the monarchy's workload.
The prince, who previously visited Australia in 2003, leaves the country tomorrow to attend a charity event in Dubai.
He follows in the footsteps of his grandfather, the Duke of Edinburgh, who took part in a review in Sydney in 1986.
The RAN said there were also ships from Brunei, China, France, India, Indonesia, Japan, Malaysia, Micronesia, New Zealand, Nigeria, Papua New Guinea, Singapore, Spain, Thailand, Tonga and the United States taking part in the review.