More than 300 people were also wounded in the attacks yesterday in the Mediterranean coastal cities of Jableh and Tartus, some of them critically, the Syrian Observatory for Human Rights said.
Most of the dead were civilians, among them eight children.
The two cities, which are majority Alawite -- the offshoot of Shiite Islam followed by Assad -- had been relatively insulated from Syria's five-year civil war.
IS claimed the blasts in a statement, saying they were in retaliation for air strikes by the regime and its Russian ally and threatening "more devastating and bitter attacks".
More than 270,000 people have been killed since the conflict erupted in 2011. Millions more have been driven from their homes.