Singapore will allow entry to travellers from Australia, excluding coronavirus hot spot Victoria, beginning next week.
Vietnam is also being granted the exemption from coronavirus restrictions.
The tiny city-state last month welcomed visitors from Brunei and New Zealand, and is cautiously reopening its borders to help revive its airport, a key regional aviation hub.
The aviation authority has said there is a low risk of virus importation from Australia and Vietnam. Travellers must undergo a virus swab test upon arrival, travel on direct flights without transit and download a mobile app for contact tracing.
The changes start from October 8.
Singapore’s move is unilateral and not reciprocated by the four countries.
Transport Minister Ong Ye Kung said in a Facebook post that “with each step of safe opening of our borders, we start to rebuild the bridges and resuscitate Changi Airport.”
Singapore has managed to control the pandemic after an earlier upsurge due to infections among foreign workers living in packed dormitories. It has confirmed more than 57,000 cases of infection with 27 deaths from COVID-19.