Lake Pinatubo is a crater lake in the mouth of Mount Pinatubo, a volcano located on the borders of Zambales, Tarlac, and Pampanga in the Central Luzon region and considered dormant for 600 years until it erupted from 12 to 15 June 1991.
Lake Pinatubo measures two kilometers in diameter and 600 to 800 meters in depth. The eruption After Mount Pinatubo eruption in 1991 caused the formation of a five-square-kilometer hole. Years of rain filled the hole with water, forming a small, hot, acidic lake. More rainfall diluted the lake and cooled the water. The lake was first discovered in 1995 when several explorers found trails leading to the mouth of the volcano. There they found a lake with green waters, surrounded by barriers made of ash and rocks. Over the years, more visitors came to trek to the lake.
In November 2009, the National Commision on Indigenous Peoples confirmed that the 15, 998 hectares of land at Mt. Pinatubo, including the three-wide kilometer wide crater lake was registered at the Registry Deeds in Zambales as a Certificate of Ancestral Domain Title.
The chair of the Lubos ng Alyansa ng mga Katutubong Ayta sa Sambales (Lakas), Carlito Domulot, shared that Mt. Pinatubo is now lutan tua (ancestral land) of Aetas. NCIP Commisioner Rolando Rivera said that the Aetas' CADT covers Mt. Pinatubo.
Visitors may avail of tour packages to Lake Pinatubo, which may amount to P1,500 per head, inclusive of fees for park maintenance, the guide, a packed lunch, and the 4x4 transportation from the meeting point to the starting point of the trail. The trek through the vast rocky terrain, which the 4x4 could no longer pass through, would last about three hours. Further up the path is a stream with slippery rocks so the visitors are advised to wear a pair of sturdy sandals with good traction instead of hiking boots. 
Once at the top, visitors may descend to the shores of the lake and swim in the blue-green waters or take a boat ride to the other side (for a separate fee).
In 2001, the lake's water level reached a critical state, which roused fears that the lake would collapse and flood nearby populated areas. This prompted the Philippine government to construct a five-meter-deep drainage channel in order to drain a quarter of the lake into the River Bucao. Around 9,000 villagers had to temporarily vacate their homes during the construction of the channel and the draining of Lake Pinatubo.
- Pinatubo Volcano Philippine Institute of Volcanology and Seismology (accessed 24 March 2010)
- Pinatubo Hiking travelintelligence.com (accessed 24 March 2010)
- Filipinos return as volcano lake drains BBC News (accessed 24 March 2010)
- It’s official: Pinatubo is now owned by Aetas Inquirer.net (Accessed 11 May 2010)