The cave will reopen to tourists in 2019.
Son Doong cave tour in 2018 was full with 873 local and international visitors, including 290 adventurers from the US and 154 holidaymakers from Vietnam.
This has brought the total number of visitors to the world’s largest cave to 2,900 since tours were first available in 2013.
Currently, 40 out of 400 small and large caves in Quang Binh province are open to public. However, local authority has limited the number of visitors to several caves such as Son Doong and En for further protection.