Thirlmere Lakes National Park is situated on 627 hectares and is 105 kilometres south of Sydney and 10 kilometres from Picton.

Part of the Greater Blue Mountains World Heritage Area, this park's five reed-fringed freshwater lakes, abundant with waterbirds and surrounded by quiet patches of forest, are among the last undisturbed lake systems near Sydney and have enormous scientific value.

Only low impact activities, such as walking, swimming, canoeing and picnicking are encouraged. Camping is not permitted anywhere in the park and powerboats are prohibited on the lakes.

Unfortunately Thirlmere Lakes has dried up at the moment and can be dangerous to walk across due to deep mud. An investigation is underway to try and determine why this has happened.

Walking access into the Nattai Reserves is still possible.