Many of the discoveries are of multiple-planet systems much like our own solar system, the space agency said Wednesday.
Nearly 95 percent of these planets are smaller than Neptune, a significant increase in the number of known small-sized planets more akin to Earth than previously identified exoplanets outside our solar system, NASA officials said.
"The Kepler team continues to amaze and excite us with their planet hunting results," said John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington. "That these new planets and solar systems look somewhat like our own, portends a great future when we have the James Webb Space Telescope in space to characterize the new worlds."
Kepler observed hundreds of stars that have multiple planet candidates to verify the 715 new worlds, NASA said.
"Four years ago, Kepler began a string of announcements of first hundreds, then thousands, of planet candidates -- but they were only candidate worlds," said Jack Lissauer, planetary scientist at NASA's Ames Research Center in Moffett Field, Calif. who led the research team. ""We've now developed a process to verify multiple-planet candidates in bulk to deliver planets wholesale, and have used it to unveil a veritable bonanza of new worlds."
The latest discoveries bring the confirmed count of planets outside our solar system to nearly 1,700, NASA said.