Porsche did not confirm if the two would carry the 2016 or 2017 designation.
U.S. launch timing and pricing has not been announced either.
"The 718 designation is a reference to the ground-breaking sports car Porsche introduced back in 1957, which achieved great success in a number of renowned car races," the German automaker said in a statement.
Porsche built the midengine 718 from 1957-'62 as a successor to the 550 Spyder.
In addition to the heritage name, the 718 Boxster and 718 Cayman "will share more similarities than ever before — both visually and technically," Porsche said.
Both will use turbocharged four-cylinder engines, but technical specifications have not been released yet.
Porsche hinted hybrid technology may be part of the equation.
It noted that the 919 Hybrid racecar "serves as a platform to further fundamental technology research for future production models, combining two different energy recovery systems with a 2.0-liter four-cylinder turbocharged engine."
"The roadster (Boxster) will be positioned at a higher price level than the coupe — as is the case with the 911 models," Porsche said.
Edmunds says: Car shoppers making long-range plans should expect to see some name changes for the Boxster and Cayman when they step into Porsche showrooms next year.