Around 220 divers, including those clad in Santa Claus costumes, took turns posing for photos near a Christmas tree installed on the seabed during an event at the Izu Oceanic Park in Ito, southwest of Tokyo.

The 5-meter-tall tree, decorated with "flower" and "fish" ornaments made using seashells, was installed on the bottom of the sea some 20 meters deep from the surface.

"The tree was huge and looked fantastic. I really enjoyed putting on the Santa costume," Atsuko Nakamura, 36, from Tokyo, said after the event in the sea Saturday where the temperature was 19 C, warmer than the air.

The operator of the park offers Santa costumes for divers free of charge and an undersea postbox near the tree so divers can drop off waterproof Christmas cards until Dec. 25.