President Barack Obama and his family spent a warm and sunny Tuesday afternoon at one of the most popular snorkeling spots on Oahu, where they released four green sea turtles into the water.

The Obamas arrived at Hanauma Bay Nature Park after a scenic, 40-minute drive from their multimillion-dollar rented vacation home on Kailua Beach. The park is a favorite destination for the Obamas, who make an annual trip there during their Christmas holiday in Hawaii — always on Tuesdays, when the park is closed to the public for maintenance.

This year the president and his family released four green sea turtles into the bay’s clear blue water. The 18-month-old turtles were born at Sea Life Park, a nearby marine sanctuary and aquarium that boasts of being the only place in the U.S. that raises green sea turtles in captivity.

The president and his daughters, Malia and Sasha, enjoyed their turtle experience so much that they decided to make a stop at Sea Life Park later in the day. The president appeared briefly before cameras as he left the park, climbed into a waiting SUV and headed back to his vacation rental.

The president has stayed largely out of the spotlight since arriving Friday evening in Hawaii. He spent a low-key holiday with his family, attended Christmas church services and visited service members stationed at Marine Corps Base Hawaii at Kaneohe Bay.

Obama also has hit the golf course, worked out at the gym on the Marine base and taken wife Michelle Obama out to dinner.

Behind the scenes, the president is being briefed by a small cadre of traveling staff on domestic and international developments, including his administration’s debate over whether to allow Yemen’s outgoing leader to come to the U.S. for medical treatment. Obama also announced two nominees to the Federal Reserve Board of Governors on Tuesday.

Obama has no public events planned during his vacation, which is expected to last until shortly after New Year’s Day.