Tham Luang cave complex in Chiang Rai's Mae Sai district will reopen on Friday after it was closed to visitors due to the Covid-19 pandemic.

Visitors will be able to trek along the newly extended trail inside the cave, which now includes the underground chamber that was used by Navy seal divers in the dramatic rescue of the 12 young footballers and their coach who were trapped in the cave in 2018.

The chamber, which is located some 200 metres from the mouth of the cave, is the only cave in the system which the public can access. Caves which are deeper in the complex will remain off-limits to tourists.

The chamber where the footballers and their coach were trapped is actually located 2.43km from the mouth of the cave. It would take days to walk there, the park chief said.

A trip to the accessible part of the cave will take about 15 minutes, though a guided trip may take about 30 minutes.

The cave will limit visitors to a maximum of 40 at any given time.

Visitors must be fully vaccinated or have passed a Covid-19 test before entering the national park.