They said they only kissed on the cheek, but pleaded guilty to charges of consuming alcohol, which landed them a fine of 1,000 dirhams (270 dollars or 180 pounds) each.
The two are entitled to challenge the sentence in the cassation court, the highest court which can review cases in the United Arab Emirates, a Gulf state made up of seven members including Dubai.
They were convicted in January and sentenced to one month in prison, but were released on bail with their passports held by the authorities.
Hosani said the defendants were in the court building but did not enter the courtroom to hear the verdict, adding they have to challenge the sentence, or hand themselves immediately to serve it.
He said he would discuss with the defendants whether they wish to take the case to the cassation court, but that "the hope is dim" to overturn the verdict.
The lawyer underscored that the cassation court would not look into the case as such, and would rather "verify whether the court of appeals has applied the law properly, or not."
Hosani had told court last month that the only witness, a 38-year-old Emirati woman, had presented different statements.
"She told the police that she saw them kissing, while she told the prosecution that her children saw them," he said, adding the defence is arguing that the couple only kissed on the cheek "as a greeting" which is allowed.
Dubai, which despite its pro-Western outlook still adheres to certain strict Islamic rules and bans sex out of wedlock, is a popular destination for British tourists and expatriate workers.
Around 1.1 million Britons visited the United Arab Emirates in 2009, and more than 100,000 British nationals live in the country.
In 2008, a British couple, Vince Acors and Michelle Palmer, were convicted of having sex on the beach in Dubai but an appeals court suspended their three-month jail term.
Acors and Palmer, both in their thirties, were expelled from the Gulf Arab country, however, and fined 1,000 dirhams for drinking alcohol.
A mother-of-two and her alleged lover, a fellow Briton, were convicted of adultery and jailed for two months in June 2009 after her estranged British husband tipped off police who caught the couple leaving a Dubai hotel at 2:30 in the morning.
The Foreign Office warns Britons travelling to the UAE that the Muslim country has strict rules on public displays of affection, and points out women should dress modestly in public.
"Proportionally, Britons are most likely to be arrested in the UAE than any other country in the world," says the travel advice, also highlighting the UAE authorities' zero tolerance on possession of drugs.