The tourist, identified only as Mike, went bungee jumping at the Changthai Thappraya Safari and Adventure Park.
He jumped off a 10-story-high podium, and the video shows him falling into the lake after the rope snapped while he was a few meters above the water.
He blacked out briefly before regaining consciousness and swimming out of the water with the help of park employees.
He was rushed to a local hospital.
Mike told CNN: "It was really high and so I closed my eyes. I planned to open my eyes again when I bounced back up. I realized the cord had snapped when I opened my eyes and I was surrounded by water."
Mike said he also had a lung infection and was hospitalized for three days after returning to Hong Kong.
His medical bills of around HK$50,000 ($6,369) were covered by travel insurance.
He said the park offered him only HK$2,300, HK$1,800 for medical fees and a HK$500 refund of the jump fee.
He has written a complaint to the park and the Tourism Authority of Thailand.
Located in the northwest of Pattaya, the amusement park offers various activities like ziplines to live-round shooting.