During an appearance on Fox News Channel, host Neil Cavuto mentioned reports that Obama is slated to take a three-week trip to Hawaii this time, and asked Romney how long a break he would take if elected president.
"A lot shorter than that, I tell you that," he said, pledging to "work my day and night off" to help rebuild the American economy.
"If I'm lucky enough to be president, I'm not going to be playing, what, 80 or 90 rounds of golf. I'm not going to be going off to Hawaii or any other spot for three weeks."
On Monday, Romney had mocked Obama's fondness for golf, telling supporters: "It's time to have a president whose idea of being 'hands on' doesn't mean getting a better grip on the golf club."
Tentative plans do call for Obama to leave for Hawaii late next week, and stay at his usual rental home on Oahu through New Year's Day. Last year, the trip included a few rounds of golf, trips for shaved ice with his family, and a luau with friends.
But the White House, with any trip outside Washington for down time, emphasizes that no president can ever truly be on vacation. One year earlier, Obama's holiday trip was overtaken by national security concerns after an attempted Christmas Day bombing of a Detroit-bound airliner.
Romney's jab at Obama's Hawaii plans also are notable because the former Massachusetts governor himself vacationed in Maui last Christmas.
Democrats returned fire quickly.
"A look at his record as governor paints the picture of someone who frequently vacationed his 'day and night off' and spent 212 days of his last year in office out of state campaigning his 'day and night off' for president," the DNC said in an email listing past Romney vacation trips.