The Duke of Cambridge has been meeting teenagers during his visit to Malta - impressing them by scoring the winning goal in a table football match.
The second day of his trip also saw him attend a Mass to celebrate the country's 50 years of independence.
He is a replacement for the pregnant Duchess of Cambridge, who had to withdraw on doctors' advice after suffering severe morning sickness.
It would have been her first solo official overseas visit.
Prince William is understood to have been in regular contact with the duchess over the weekend to update her about the trip.
During a visit to an access centre for young people and adults from an impoverished area of Malta, he joined a pair of teenagers who were losing a game of table football.
He scored two goals, much to the delight of 17-year-old team-mate Kayleigh Cioffi, a regular user of the Agenzija Appogg centre in Birgu.
She said: "He's better than me, and he helped us win. He was so, so nice. He said that he would love to spend a summer here."
The prince also sat on a beanbag to join three teenage boys who were playing a computer football game.
When he met childcare student Janet Desira at the centre, he joked that the 17-year-old could "do some babysitting" for him, saying of toddler Prince George: "He's busy, they're very hectic at that age."
Prince William asked about her exams before referring to his own helicopter studies for his air ambulance job, saying: "I've got to do 14 exams by Christmas."
From next spring, he is to work for the East Anglian Air Ambulance for at least two years.
Duchess 'feeling better'
After leaving the centre, the prince watched a dance performance by women in traditional costume from the neighbouring island of Gozo and then went on a walkabout.
He met a group of young Boy scouts from the 1st Cospicua troop and was handed a loom band, which he put on his wrist.
Prince William was surrounded by well-wishers as he walked to Birgu's marina for a boat tour of the harbour which separates it from the capital Valletta.
He was transported in a small craft called the St Angelo - the same vessel that took his grandmother the Queen around the harbour during a 1949 visit.
For the last engagement of the tour, Prince William was guest of honour at a garden party in the grounds of British High Commissioner Rob Luke's official residence.
He told expat Peter Robinson, 71, that Catherine's condition has slightly improved.
Mr Robinson said: "He was very happy to be here. William told me that Catherine was sad to have missed the trip but we both agreed that the hot weather would have been too much for her.
"I asked how she was doing and he said he spoke to her this morning and she was feeling a little better."
The party was held to mark the anniversary of the day Malta gained its independence from the UK, on 21 September 1964.
During the earlier Mass, prayers were said and hymns sung in thanksgiving for the five decades of self-rule.
Leading national figures were also at the service at St John's Co-Cathedral in the capital Valletta.
It is believed to be the first time that the prince has attended a public Catholic Mass.