Osbourne, 26, posted his version of the Oct. 8 emergency on his Facebook page and credited a Japanese doctor and other onlookers who helped keep the woman alive until an ambulance arrived.
"The last thing I want to do is take all of the credit when in fact there were a few people who helped save her life," Osbourne wrote.
People magazine said Osbourne, who was on his honeymoon at the time, performed CPR on the woman, using training he received as a police reservist.
"I am not an EMT or paramedic, but I have assisted in resuscitating individuals in the past," Osbourne said.
Osbourne said the woman had been pulled from the ocean and was being given CPR by the other onlookers by the time he got to the scene, People said.