"I know what I'll do right after the next president's inaugurated," Obama said at the end of an interview on the microblogging platform Tumblr, aimed at an audience in their 20s.
"I'll be on a beach somewhere, drinking out of a coconut," Obama said, drawing laughter from a group of Tumblr users who were in the White House state dining room for the interview.
But first, the president said he is focused on "making sure that I make every day in the next two-and-a-half years count" in his time in office.
After the next election, Obama said he plans to work with young Americans to promote leadership after his presidency and wants to counter cynicism he sees in the millennial generation.
"You guys are fed a lot of cynicism every single day about how nothing works and big institutions stink and government's broken," he said.
"Look out on the horizon, and there's a lot of opportunity out there," he said. (Reporting by Roberta Rampton and Steve Holland; Editing by Jonathan Oatis)