In the first incident, two bombs exploded late Wednesday in the central island of Leyte, wounding 27 people who were watching a boxing match in Hilongos, police said.
Another unexploded bomb was also found in the town, which is about 620 kilometers (385 miles) south of Manila, said the town's mayor Albert Villahermosa.
A bomb went off on a highway on the southern island of Mindanao barely an hour later, wounding six people, the military said.
"A lamppost was catapulted from the impact of the explosion," said Lieutenant Colonel Edgar Delos Reyes.
The blast in Aleosan, hundreds of kilometers south of Hilongos, was close to the site of a Christmas Eve church bombing that injured 13.
Police said it was too early to say if the Wednesday bombings were connected or what the perpetrators' motives might be, AP reported.
Mindanao has been wracked by bombings and other forms of violence carried out by those who consider the region as their ancestral homeland, leading to separatist conflicts with the government.
In the deadliest recent such attack, 15 people were killed in an explosion in President Rodrigo Duterte's hometown of Davao in Mindanao in September.