SINGAPORE - The much-anticipated air travel bubble to allow quarantine-free travel between Singapore and Hong Kong is set to take off on May 26 - six months after its initial planned launch.

Originally planned to start in November last year, it was deferred by both parties due to the worsening Covid-19 situation in Hong Kong.

Singapore's Ministry of Transport (MOT) said on Monday (April 26) that the travel bubble will have a cautious start. There will be one flight a day in each direction, capped at 200 passengers on each flight for the first two weeks.

The numbers will be reviewed thereafter.

Rules for travel will also be tightened. Travellers must have remained in either Singapore or Hong Kong in the 14 days prior to departure, and the 14-day period must exclude any time spent in quarantine or under stay-home notice arising from their last return to Singapore or Hong Kong from overseas.

In addition, they must now download and install Hong Kong's LeaveHomeSafe app on their mobile devices prior to leaving Singapore for Hong Kong.

If the air travel bubble has to be suspended when the seven-day moving average of the unlinked community cases in either Singapore or Hong Kong increases to above five, it can resume only when the Covid-19 situation has stabilised.

As agreed under the original deal, passengers from both sides have to be tested negative for Covid-19 before they can board the direct flights.

There is now an additional requirement for Hong Kong passport holders leaving the territory. They must be fully vaccinated before taking the bubble flights.

This vaccination requirement will not apply to Singapore citizens and others using non-Hong Kong travel documents for departure.

In Hong Kong, Secretary for Commerce and Economic Development Edward Yau said the key control element under the arrangement is to have pre-departure tests, when asked why Singaporeans flying to Hong Kong on bubble flights are not required to be vaccinated.

"In the case of Hong Kong, we have made provisions for the entire community to be vaccinated so as to protect themselves and the purpose of asking Hong Kong residents going out to have vaccination prior joining the scheme is in fact protecting their own health," he said. "This would be an additional safeguard for our people."

He added that the goal remains to strike a balance between public health and travel convenience.

In Singapore, Transport Minister Ong Ye Kung said: "I am happy that Hong Kong got the Covid-19 situation under control. It has been a long few months, but the conditions are now ripe again to relaunch the ATB (air travel bubble). Both sides will need to stay very vigilant in the next one month, so that we can launch the first flights smoothly."

Singapore and Hong Kong will closely monitor the Covid-19 situation from now to the targeted launch date of May 26, and will proceed with the launch if the situation continues to be steady and under control in both cities, the statement added.

Singapore Airlines (SIA) said the first bubble flight to Hong Kong, SQ882, will depart on May 26 at 8.40am.

SIA welcomed the decision to start the air travel bubble. "This is an important milestone in our recovery from the Covid-19 pandemic, and helps to establish confidence in the safe resumption of international air travel with the necessary protocols in place," its spokesman said.

The travel bubble, which was initially scheduled to begin on Nov 22, was postponed on Nov 21 after a spike in Covid-19 cases in Hong Kong.

On Dec 1, the Civil Aviation Authority of Singapore said both cities had decided to defer the start of the travel arrangement to beyond 2020, given the high number of unlinked cases in Hong Kong.

Hong Kong Chief Executive Carrie Lam had said on April 13 that she expects "an early indication of agreement between the two sides" on the travel bubble.

The next update came on April 14 when Mr Ong announced that details of the arrangement were being finalised.

Some experts have pointed out that such travel bubble arrangements are fragile and can easily burst given the uncertain Covid-19 situation.

Australia and New Zealand had this month started a long-awaited quarantine-free travel bubble on April 18.

But the arrangement was paused just five days later on April 23, after a Covid-19 outbreak in Australia.