An attack against a police station in the province of Urozgan killed at least 12 people and wounded five others, the BBC reported.
Most of the victims were believed to be police officers, including a chief identified as Obaed Ullah, who were having lunch when the attacker struck, the report said.
In the second attack, a bomber detonated his explosives in the southern province of Kandahar, near the border with Pakistan, killing 10 people, including an Afghan border police officer, officials said.
Security forces said the attacker entered Afghanistan from Pakistan.
The third occurred at a border crossing between Afghanistan and the village of Chaman, in Pakistan's violent Balochistan province, the Pakistani newspaper Dawn reported. The Press Trust of India said nine people were killed, including six border officers.
A bomber on foot detonated himself near a border vehicle at the Friendship Gate. Afghan officials told Dawn Cmdr. Akhtar Muhammad appeared to be the intended target but survived.
The crossing is a major supply route for NATO forces in Afghanistan. It was closed after the bombing.