Abandoned open pit mines when properly managed can be an important settlement and eco-tourism sites. The Pulang Lupa Lake – an abandoned mercury open mining pit in Puerto Princesa City supports a number of settlers and important wildlife. With limited information about its status, this study was conducted to determine the lake’s water quality and its potential for eco-tourism. Water physico-chemical parameters were within the permissible limits sets by the Department of Environment and Natural Resources for Class C water during the rainy but not in summer season. Water samples for both seasons were positive for total and fecal coliform. The lake serves as important source of fish for informal settlers and the presence of several bird species makes it a potential bird watcher’s destination. Information and education campaign among the residents around the lake and strategic environmental plans are needed for its sustainable utilization.