Edwin "Eddie" GrandSmith is the grandson of the wealthy resort chain CEO Donovan GrandSmith.
Eddie looks a lot like his grandfather and even wears the same clothes as him. He has a dark maroon sweater with a brown turtleneck and white pants. He has black hair and blue eyes
Eddie tends to be arrogant. When he first met Ben and Gwen, he was rude and off-putting. After his grandfather convinced him to give a tour for them, he mentioned how good a swimmer he is, causing Ben to mock him. He strongly dislikes how his family solves every problem with money. However, at the end of the episode, he became cheerful and gave his grandfather a hug.
Eddie was in the underwater resort with Ben and Gwen when it was attacked by some robotic aliens. After noticing a series of "surprisingly helpful aliens" appear and that Ben always seemed to disappear right when they showed up, he was able to figure out Ben's secret. Eddie was able to lead Ben and Gwen to the Undersea Manta Ray, and with Ben's help as Upgrade.
- They Lurk Below (first appearance)
- His grandfather called him Edwin throughout the episode. At the end of the episode, he said that he preferred Eddie.