A passenger aboard a Royal Caribbean 'cruise-to-nowhere' from Singapore tested positive for Covid-19, forcing around 2,000 guests to be quarantined in their cabins and the Quantum of the Seas ship to return to dock on Wednesday.

Singapore has been piloting the trips, which are open only to residents, make no stops, and sail in waters just off the city-state.

The global cruise industry has taken a major hit from the coronavirus pandemic, with some of the earliest big outbreaks found on cruise ships. In one case in February off the coast of...