The two men "committed suicide by detonating their explosive belts" during a security operation against a suspected "terrorist" hideout in a southern district of Jeddah, the region's authorities said on Twitter.
They did not give immediate details about the operation or identify the bombers, but said the raid had been successfully carried out after a shootout with the suspects.
Earlier this month, Saudi security forces shot and killed two suspected jihadists including an explosive belt maker during a police operation in the north of Riyadh.
Since late 2014, IS has claimed a series of bombings and shootings against Shiites in the Sunni-majority kingdom, as well as against security forces.
Saudi Arabia is a member of the US-led international coalition that has been battling IS jihadists in Syria and Iraq.