After a brief news conference yesterday, President Obama returned to the business of vacationing and was whisked to Hanauma Bay, where he spent the day snorkeling and picnicking with his family and several close friends.

Obama spent about 2 1/2 hours at Hanauma Bay, which was closed yesterday to the public, as it normally is on Tuesdays. But don't expect to see photos of Obama romping in the waves — reporters weren't allowed to get close enough to the bay to spot Obama and didn't catch a glimpse of him leaving.

Dozens of onlookers along the road did get to see the president's motorcade zoom past, though, as it returned to Kailua. At Sandy Beach, where Obama last bodysurfed as a U.S. senator in August 2008, swimmers yesterday stood on the roadside clad in their bikinis and board shorts to flash shaka signs.

In Waimänalo, people came out of their homes to watch Obama pass.

The president and his family arrived on O'ahu on Christmas Eve, and are expected to return to Washington on Jan. 4. The vacation has so far been very low-key, with jaunts to the golf course, the beach and out to dinner.

At the same time, Obama has been trying to tackle security concerns in the wake of the foiled Christmas Day attempt to blow up a Detroit-bound jetliner. Yesterday, in a news conference, Obama called the incident a "systemic failure."

"When our government has information on a known extremist and that information is not shared and acted upon as it should have been, so that this extremist boards a plane with dangerous explosives that could cost nearly 300 lives, a systemic failure has occurred," he said. "And I consider that totally unacceptable."

Obama also addressed the American public on Monday.

Both news conferences, though, have been short. And Obama has quickly jumped back into his vacation.

White House officials have said that the president wants to reassure the public that he is able to deal with the incident (and any other crises) from his vacation home in Kailua, and they say he has been getting regular briefings.

Also yesterday, Obama went to Marine Corps Base Hawai'i to work out as he has daily. He left for the "Semper Fit" gym at about 7:25 a.m. and wrapped up there about an hour later, returning to his Kailua compound for about two hours before heading back to the Marine Corps Base for the news conference.