Lam Khlong Ngu National Park chief Satit Pinkul on Wednesday (January 15) announced the openings for Tham Sao Hin (Stone Pillar Cave) and Tham Nok Nang-aen (Swallow Cave).

Both are within the park in Kanchanaburi’s Thong Pha Phum district.

Advance registration for individual visitors up to groups of 10 is being accepted from February 3-7, daily from 1-3pm.

Visitors should be 15 to 60 years old and able to swim, since some areas of the caves are semi-submerged. They should be healthy, with no congenital disease or respiratory or blood-pressure issues.

Satit said this is the safest time of year to see the caves – Tham Sao Hin with stalagmites exceeding 62 metres in height and Tham Nok Nang-aen with its gorgeous subterranean vistas and thousands of nesting birds.