Watson wept in court as he listened to a portion of the police interview where he recalled the moment he was told attempts to resuscitate his wife failed.
"I pretty much lost it," Watson told Townsville detectives.
Watson and Thomas married in their home state of Alabama just 11 days before her October 22, 2003, death.
The newlyweds were in Australia on their honeymoon and were on the first day of a seven-day diving trip off the coast of Queensland when she died.
Watson told police "five to seven minutes" into their dive over the SS Yongala shipwreck they struggled against a strong current, Thomas got into difficulty and at one point struck his mask and air regulator.
He said he thought he kicked Tina with his fin to get some space from her and she floated away from him.
"She was out of arm's reach," Watson said in the police interview. "I couldn't grab her hand."
He swam down to get her but she was sinking just as fast, Watson told police. He decided against chasing her to the seabed and instead headed for the surface.
He said he encountered two other divers in the ascent. "I remember shouting through my regulator 'Tina, Tina, Tina'," he told police.
Townsville detective senior constable Kevin Gehringer, who conducted two taped interviews with Watson, testified that, on the day Thomas died, Watson became agitated when told police could not give him back his dive computer.
The dive computer, which Watson wore on his wrist while diving the Yongala with Tina, was held by police to assist with their investigation.
Watson, 34, is accused of murdering Tina for pecuniary gain while diving the Yongala.
Prosecutors allege Watson planned the murder in Alabama before he flew with his bride to Australia.
Watson has already served an 18-month jail sentence in Queensland after pleading guilty to the manslaughter of his 26-year-old bride.
- AAP
