BUCHAREST—After 40 years at sea, on his last voyage before retirement, Captain Dan Sandu slipped into his cabin on the MV Vantage Wave, a cargo ship sailing away from India, feeling unwell. “Don’t worry,” he typed in what would be a final email to his wife in April. “Everything will be fine.”

Last month, the ship, by then floating off the United Arab Emirates, sent what had become a familiar plea. Captain Sandu was dead and his body was in the ship’s walk-in freezer. For six months, it had traveled thousands of miles lying...

BUCHAREST—After 40 years at sea, on his last voyage before retirement, Captain Dan Sandu slipped into his cabin on the MV Vantage Wave, a cargo ship sailing away from India, feeling unwell. “Don’t worry,” he typed in what would be a final email to his wife in April. “Everything will be fine.”

Last month, the ship, by then floating off the United Arab Emirates, sent what had become a familiar plea. Captain Sandu was dead and his body was in the ship’s walk-in freezer. For six months, it had traveled thousands of miles lying near the crew’s meat and vegetables. They needed to get him back to Romania.

It was the 13th country the Vantage Wave petitioned. All had refused to receive the body.

The plight of Capt. Sandu, a 68-year-old born near the Black Sea, who decorated his home with mementos from a life on the ocean, had become a diplomatic incident. “All we wanted was to get our father home,” said his son, Andrei Sandu, also a ship captain. “How can this happen in 2021?”

Strict and uneven rules governing the world’s ports prevent the unloading of bodies suspected of being infected with the coronavirus. Though the pandemic has eased somewhat, the restrictions remain, leaving ships like the Vantage Wave to cross oceans in search of a port to offload a fallen crew member. There are now numerous corpses stuck on the world’s cargo ships, usually stored in freezers meant for food.

In September, a 23-year-old seaman from Ukraine died aboard a Swiss-flagged bulk carrier anchored at China’s southeastern port of Rizhao, an apparent suicide. After Chinese authorities refused to take his body, the ship traveled for nearly two months and more than 5,000 miles, to Vancouver, where the Royal Canadian Mounted Police agreed to help repatriate his body. It’s still not home.

The MV Vantage Wave, the last ship on which Capt. Dan Sandu sailed.

Photo: Harvey F. Wilson

The corpse of a Syrian cook who died off the coast of Venezuela was trapped aboard for four months. And when an Italian cargo-ship captain died off Indonesia, his body stayed in a storeroom for six weeks, for lack of cold-storage large enough, decaying in the tropical air. There currently are four seafarers’ bodies stuck aboard cargo ships, the International Maritime Organization says—as well as 36 urgent cases involving medical or humanitarian emergencies.

An Indian sailor sick with severe Covid-19 was denied entry to Singapore, Malaysia and several other Asian ports before being ferried back to India and put on a ventilator. When a Chinese officer aboard the Newmax bulk carrier collapsed, vomiting blood, Chinese port officials allowed him ashore briefly in an ambulance before returning him to the ship with some pills.

“We are spending our lives here on board to bring the goods to your house,” said the Newmax’s captain, Tymur Rudov,

in a YouTube video. “What do we get in return?” he shouted into the camera. “We are not allowed to even be ill! We just have to die.”

International maritime law says shipowners must see that crews get home after assignments, but the obligation vanishes the instant a sailor dies, said Jason Chuah, a professor of maritime law at London’s City University.

And while insurance companies are meant to contribute to the cost of burying or cremating a dead seafarer, under a pact called the Maritime Labor Convention, the treaty doesn’t require them to get a body home. For the owners of ships full of cargo to be delivered on deadlines, returning to port to deposit a corpse can be onerously expensive.

That leaves shipmates, lawyers, diplomats and above all families to navigate the ever-shifting pandemic-era regulations of the international seafaring bureaucracy. The crew of one vessel declared force majeure, the “act of God” clause, which allowed them to sail more than 6,000 miles from Indonesia to Italy to return a dead captain.

“The depressing thing about this is that deceased or dead people have no rights whatsoever,” said Mr. Chuah. “It is a huge problem and reflects so poorly on our common humanity.”

The body backlog is part of a broader problem of seafarer abandonment in the era of Covid-19. More than 1,000 people were left stranded on container ships and bulk carriers this year without pay, according to estimates by the International Transport Workers’ Federation. It’s a record stemming both from pandemic-induced trade disruptions and the competitive nature of the lightly regulated global shipping industry.

Family pictures from Capt. Sandu’s career at sea.

An Ocean Life

Capt. Dan Sandu nearly didn’t board the Vantage Wave.

His wife, Gabriele, pleaded with him not to take what he promised would be a final assignment. She had seen reports of a new Covid-19 variant rampaging through India, where the ship would start its voyage.

The couple, married for 44 years, were planning the next stage of their life, searching for an apartment in Bucharest to be closer to their grandchildren. “He made a promise to the owner and so he went,” said Gabriele, as she pushed black and white photos of her husband as a young seafarer across a coffee table. “But I had a bad feeling. I said it to him many times, he shouldn’t go.”

Capt. Sandu was in the twilight of a career that started under the Communist regime of Nicolae Ceausescu and lasted through the end of the Cold War and waves of globalization. Working for state shipping company Navrom was one of the few jobs that let Romanians travel abroad, and his wife’s father, brother and cousin, all sailors, encouraged him to join.

His first voyage was to China in the 1970s, months after Chairman Mao’s death, where he brought some shell-shaped porcelain bowls. In the 1980s, he began to smuggle souvenirs and consumer goods in his suitcase: a kilo of coffee, a brass Sphinx statue from Egypt, clothes for his wife, a wooden elephant statue from Southeast Asia for his kids and a VCR.

“We could watch movies while others only had two hours of TV,” said Andrei, who would rifle through his father’s bags when he returned.

The son followed his father into shipping, but as the industry shifted in the early 2000s, the elder Sandu weighed whether to quit. Crews had become smaller and captains spent much of their time staring into a screen. Telegrams to contact home had given way to satellite phones, then a rudimentary ship email system and finally WhatsApp.

In 2017, Chile awarded Capt. Sandu its Magellan certificate for navigating South America’s treacherous straits as did the 16th-century explorer. But “since 10 years ago, he was just fed up with this job,” said Andrei. “It’s not fun anymore…Now it’s fast fast fast, everything must go faster.”

When the two discussed quitting, they joked it was too late to chase another career: “What am I going to do, wash the dishes?” Andrei recalls his father saying.

Last Voyage

On March 27, Capt. Sandu arrived in India to board the Vantage Wave, laden with 25,000 tons of aluminum ingots bound for the Chinese port of Guangzhou. A dayslong stream of inspectors, port officials and shipping agents boarded the giant red-hulled bulk carrier capped with four rusting cranes.

Two weeks later, Capt. Sandu called his wife with a worrying update. Two members of the crew were sick, and he thought it was Covid-19. One had a 103.1 degree fever. The bosun had gone ashore twice for hospital treatment and come back with a bag of pills. He tested negative, said the ship’s Greek owner, Vantage Shipping Lines SA.

On April 15 the ship set sail, heading southeast toward Singapore, leaving one crew member behind because it was taking too long to get his hospital results. “I wonder who will be the next case?” Capt. Sandu emailed his wife the next day.

She received another message two days later. Capt. Sandu said he had “a little cold” and had isolated himself in his cabin. The ship’s chief officer was now in charge.

The crew reported his symptoms to a medical center on land, which concluded Capt. Sandu likely didn’t have Covid, Vantage Shipping said.

“Everything will be fine,” he told his wife in a 9:11 a.m. email.

Two days after that, while driving through rush-hour traffic in the Romanian capital of Bucharest, Andrei Sandu got a call. His father was dead.

“I parked my car and stayed there for a half-hour,” he said. “I don’t know how I managed to get home.”

Andrei Sandu at his parents’ home.

The crew carried Capt. Sandu’s body to the ship’s walk-in freezer, a 15-square-meter room chilled to minus 30 degrees Fahrenheit, which normally housed weeks of meat, vegetables and other frozen food. There was no body bag, so they wrapped their captain in fireproof clothing and a tarpaulin.

At this point, about 1,000 miles at sea, the ship could have turned back and tried to deliver his body in India, where Covid-19 restrictions weren’t as rigid as at the East Asian ports the ship was churning toward.

Backtracking would delay cargo delivery, said Nicholas Papalios, founder of Vantage Shipping. Also, India might not take the body of the captain, who had died in international waters, Mr. Papalios said, and returning to India might expose the crew to Covid-19.

“The rest of the crew had zero symptoms,” he said. He declined to put Wall Street Journal reporters in touch with other crew members.

Just before 2 a.m. on April 22, the ship arrived in Indonesia with a request to take Capt. Sandu’s body ashore.

Port authorities refused. The crew on board turned argumentative, frustrated with the imbroglio and the treatment of their captain’s body.

Vantage Shipping sent new crew members, including a Greek senior engineer to help quell the protests. For nine days, the ship and its tense crew held tight off the sweltering shore of Indonesia, seeking a solution.

Ports in Singapore, Malaysia and Thailand were receiving requests from Vantage Shipping as the shipowner searched for a place to unload the body, said Mr. Papalios.

“They didn’t even want our vessel to enter their waters,” he said.

Dan and Gabriela Sandu with their grandson.

Photo: Sandu family

Thousands of miles away, Romanian diplomats in Beijing and Shanghai lobbied the Chinese government to allow the repatriation. The response was “a clear refusal,” according to a memo from the Romanian foreign ministry.

On April 30, Romania’s ambassador to China sent a sharp warning to Vantage Shipping: China would not allow the body onshore.

The Chinese government didn’t respond to requests seeking comment.

The ambassador told the ship it should return to the port of origin, India, which under the Romanian government’s interpretation of international law would be “the only one allowed to oblige berthing in these conditions.”

Mr. Papalios made a different determination: He set course for Guangzhou. “We had to call on China no matter what,” he said. “We had to discharge the cargo.”

Just after sunset on May 6, the ship stopped its engines outside Guangzhou. Days turned to weeks as it sat in the South China Sea just beyond the city’s glimmering skyline.

Food and water began to run low, and requests for provisions were denied by Chinese authorities, according to the seafarer charity Human Rights at Sea, which published an urgent call for help. The shipowner said it was spending $5,000 a day to keep the vessel running.

On land—in China and Romania—diplomats, insurers and agents tried to secure an exemption to Beijing’s strict Covid-19 policy. In Bucharest, Romania’s foreign ministry summoned Chinese diplomats but was again rebuffed.

Gabriela Sandu, the captain’s widow, outside their home in Sinaia, Romania.

The shipowner reached out to the Sandus with a counterproposal, which wasn’t acceptable to the family. The body of the captain would be cremated, or failing that, thrown into the sea.

“They said you won’t get the body back or it will be in the water with the fishes,” said Andrei. “They were treating my father like a piece of garbage.”

Mr. Papalios said the suggestions were made only as the company explored all possible solutions. Burial at sea was never a realistic possibility because it wasn’t legal without an autopsy, he said.

For two months, the Vantage Wave waited in the South China Sea, according to ship-tracking data. Finally, on July 17, a Chinese official called and said a pilot boat was coming to take the aluminum ingots, but not the body. Shortly before midnight, the unloaded Vantage Wave set sail again.

In Romania, Andrei Sandu hired a lawyer to try to get answers. His mother, having trouble sleeping, moved to Bucharest to be with her children and away from the empty mountain home.

Her husband’s story had reached the national news. Prime Minister Florin Citu, facing reporters who demanded to know how the government would stop the captain from being cast into the sea, said he would call another minister to make sure it didn’t happen.

Going through the last messages received from Capt. Sandu.

In the meantime, the ship stopped for repairs off Vietnam, where Mr. Papalios said he got false assurances from port agents that the country would take the body.

With time passing, Mrs. Sandu worried there would never be a proper autopsy delivering answers on how her husband died. On Aug. 29, she emailed embassies across Asia asking what steps the shipowner had taken with them to get her husband home.

One after the next, Romanian embassies—Singapore, Vietnam and Malaysia—replied saying the company hadn’t contacted them for help. Mr. Papalios said the company and its insurer contacted all embassies.

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The ship chugged around Singapore and on to Sri Lanka, from where, rebuffed again, it sailed west toward the Arabian Sea. Finally, in late September, the harbor master at the United Arab Emirates port of Fujairah agreed to send a team aboard, test Capt. Sandu’s long-frozen body and allow his repatriation in a zinc coffin.

The test concluded cardiac arrest was the most likely, but not certain, cause of death.

Andrei identified his father’s body when it arrived at the Bucharest Autopsy Institute, which has yet to release a report. On Oct.19, Mrs. Sandu laid her hand on a closed casket at a small funeral at an Orthodox church in Bucharest.

Meantime, the Vantage Wave was sold and re-christened Alma Del Mar, in Spanish “Soul of the Sea.”

Sinaia, the small town in Romania where the Sandus lived.

Write to Drew Hinshaw at drew.hinshaw@wsj.com, Vipal Monga at vipal.monga@wsj.com and Joe Parkinson at joe.parkinson@wsj.com