Downey Jr. wore lime green swim trunks and a white tee as he took his giggling son for a stroll along the shore. At one point, the Avengers actor dipped Exton's toes into the water. (Three days earlier, Downey Jr. was photographed perusing artist Lynne Bernbaum's gallery in the Sandy Ground village.)
The Sherlock Holmes star and his wife will celebrate their son's first birthday Feb. 7. When Downey Jr. first shared pictures of his pride and joy on The Tonight Show With Jay Leno in 2012, he explained how he and his wife chose such a unique name for their son.
"My wife's great uncle was kind of eccentric. He lives in Madison, Wisconsin," Downey Jr. said. "When he was in the fourth grade he realized he didn't have a middle name, so he changed his name [to include Exton]."
The actor also has a 19-year-old son, Indio, from his previous marriage to actress Deborah Falconer. Downey Jr. admitted he's had an "easier" time raising Exton, due in large part to his newfound sobriety.
"I'm not smoking pot," he joked. "It's difficult when you're changing a diaper and you're stoned."