At a packed regional court, the Chinese were imposed a fine of P2,000 each for the offense.
The group as a whole also had to pay a penalty of $50,000 for illegal fishing as part of a plea bargain, court officials said.
Illegal fishing fines are based on the number of boats used. The fishermen came in eight boats and could have been charged as high as $100,000 per boat but the fine was scaled down as part of the plea bargain.
Daisy Sy, an interpreter for the fishermen, informed the court that they wanted to plead guilty on being informed of the fines they would have to pay.
Several members of the group also pleaded guilty to related charges of using poison or explosives to catch fish in violation of local laws.
The accused consist of 122 Chinese from six boats picked up more than six months ago and 38 others detained on Sept. 12 off Palawan, a court official said.
Justice Secretary Hernando Perez last week called for the expulsion of Chinese Ambassador Wang Chung-qui after they quarreled over the fate of the fishermen.
Perez and Wang have since taken conciliatory actions but the Philippines has stood firm on demands that the Chinese must plead guilty or face trial.
Philippine officials had said they must pay fines and have their boats confiscated if they plead guilty.
Clerk of Court Maria Teresa Navarro earlier said 45 of the fishermen will be slapped additional charges of using poison to catch fish and of possession of endangered species.
Despite the diplomatic squabble over the fishermen, Navarro said the Chinese Embassy had not provided any interpreter and that the court even had to appoint a lawyer to represent the detained fishermen.
Local ethnic Chinese businessmen had acted as translators in the court proceedings.
Some 484 of 695 foreigners caught for poaching in Philippine waters from 1995 to June last year were Chinese, officials said.
Others were were Malaysians, Vietnamese, Indonesians and Taiwanese.
Some of the Chinese fishermen were arrested in areas of the South China Sea where the Philippines and China have territorial disputes along with Brunei, Malaysia, Taiwan and Vietnam.
However the issue of the territorial disputes was not raised in the court proceedings.
Chinese Defense Minister Chi Haotian, who is on the third day of a "goodwill" visit to the Philippines, had discussed the disputes in closed door meetings with local officials.
Defence Secretary Angelo Reyes said he and Chi had reaffirmed the position of the two countries that territorial disputes in the South China Sea "will not stand in the way of the development of the overall bilateral relations."
They also agreed "that peaceful and diplomatic solutions will be the venue for the resolution of such conflicts."
Chi was the second high-ranking official to visit the Philippines this month. China’s No. 2 leader, National People’s Congress head Li Peng, came to Manila last week.