Rescue operations were underway on Thursday to locate 29 missing people after a ferry sank off Indonesia's popular resort island of Bali, leaving at least five dead.

According to the National Search and Rescue Agency, 31 people were rescued from the vessel, which had 53 passengers and 12 crew members on board when it sank on Wednesday night.

“The ferry is completely submerged, and there’s a chance some people are trapped inside. However, for now, we’re concentrating the search on the water’s surface,” said Nanang Sigit, head of the Surabaya Search and Rescue team.

The five recovered bodies will be returned to their families in Banyuwangi, East Java, Sigit added.

Authorities said the KMP Tunu Pratama Jaya ferry sank roughly 30 minutes after departing Ketapang Port in Banyuwangi for Bali’s Gilimanuk Port, a short 5-kilometer (3.1-mile) journey.

Rescue teams deployed a helicopter and 15 boats to search for survivors, assisted by fishermen and coastal residents.

Rough sea conditions have complicated the search efforts. Strong waves reaching up to 2 meters (6.5 feet) and poor visibility hindered operations overnight. Although the weather improved Thursday morning, the Meteorology, Climatology and Geophysics Agency reported waves as high as 2.5 meters (8.2 feet) with strong currents and winds persisting in the afternoon.

“Today’s search is focused on the waters between the accident site and Gilimanuk Port, where initial victims were found,” Sigit stated.

An officer at the port reportedly saw the ferry sinking before rescue teams could be dispatched. "The vessel couldn’t be contacted by radio initially, but communication was eventually established with other ships. By then, the ferry was already listing," Sigit explained.

Many survivors were found unconscious after drifting for hours in rough seas, Banyuwangi Police Chief Rama Samtama Putra said.

Authorities have launched an investigation into the cause of the incident. Survivors reported a leak in the ferry’s engine room. The ferry was carrying 22 vehicles, including 14 trucks.

Relatives of passengers gathered at the port, visibly distressed and desperate for news.

Those rescued were taken to nearby medical facilities, including Bali’s Jembrana Regional Hospital.

Supardi, a 64-year-old survivor, described his harrowing experience. “When the ferry began to tilt, I thought of jumping into the sea, but the ship sank too quickly. I went down with the water, maybe 7 meters deep, before managing to climb to the surface,” he said.

He and three others stayed afloat by using life jackets until rescuers arrived.

Ferry accidents are frequent in Indonesia, a sprawling archipelago of over 17,000 islands, where lax safety standards and overloading often contribute to maritime disasters.