The incident took place in the Sufaid Sang suburb just northwest of Peshawar, the region's major city, where the trio were likely planning an attack, a senior local police official told AFP.
"Their plan was foiled when the suicide vest of one suicide bomber detonated prematurely," Kashif Zulfiqar said.
"Their target was not known but they were moving towards a crowded area where there are several police and military check posts," he added.
Police defused a jacket fitted on the dead body of a second would-be bomber and recovered a Kalashnikov rifle, eight hand grenades and hundreds of live bullets.
Mubarak Zeb, Peshawar police chief confirmed the incident to AFP.
The Pakistani Taliban and other extremist groups regularly target military and civilian installations as part of an insurgency, which has claimed tens of thousands of lives since it began in 2004.