The World Wide Fund for Nature said two fishermen tied a rope around the refrigerator-sized mammal on Jan. 1, one day after it was trapped by low tide on the shore of Palawan island's Puerto Princesa city.
After recuperating in the waist-high water, the 8.5-foot-long (2.6-meter-long) animal was declared fit for release by WWF activists.
Onlookers cheered as the sea cow - nicknamed Enero, or January in the Tagalog language - was slowly coaxed out of the lagoon.
WWF said the gentle creatures, scientifically known as Dugong Dugon, had once plied the Philippine archipelago until hunting and habitat degradation wiped out most of the herds.
The International Union for Conservation of Nature has classified the species as vulnerable or facing a high risk of extinction. There are no estimates of how many still inhabit the shallow waters of the Indo-Pacific.
Thriving populations are now protected in the Philippines' northern Isabela province, the southern Mindanao region and Palawan, WWF said.
Sea cows are thought to live up to 70 years, but females give birth to a single calf every few years. It takes up to 15 years to mature, making the species particularly vulnerable to extinction.
