Three people were arrested in Oman on Sunday for trying to smuggle more than 40 tonnes of crystal methamphetamine.
The Oman News Agency said the smugglers were foreigners but gave no more details.
Sources in Oman’s coastguard said the drugs were found on a boat.
"The vessel was stopped off the Musandam coast," a coastguard official told The National.
Musandam is Oman's northern-most governorate and juts into the Strait of Hormuz as an enclave of the UAE.
“It was not coming to Oman but sailing to another unknown destination, which we are still investigating," the coastguard source said.
"The drugs were in rice bags to make it look like it was legitimate cargo."
He said the haul was the biggest intercepted by the Omani authorities.
Smugglers use Oman’s 3,165-kilometre coastline, the longest in the Arabian Peninsula, because it is difficult to patrol because of its length and the number of vessels passing through each day.
“The Strait of Hormuz is one of the busiest patches of water in the world, due to its narrowness," said Mohammed Al Faraie, a shipping analyst.
"About 20 million barrels of oil passes every day. There are also cargo vessels and passenger cruises. It is a very difficult area to patrol."
Another coastguard official said smugglers also used fishing trawlers to carry drugs.
“These drugs mostly come from Afghanistan, India and Pakistan," he said.
"I must admit, because of the high volumes of the vessels, we miss some. It is a very difficult job to keep up with every vessel that sails in our waters in that area."
He said the coastguard intercepted other shipments of opium, cocaine and hashish.
Fishermen living in the area said it was a battle the police would never win.
“No number of patrol boats can stop all the smuggling attempts,” said Jehad Al Masroor, a fisherman in Musandam.
“I have a fishing boat and I know how easy it is to dodge a patrol boat. Most of these smugglers do it in the cover of the night.
“Besides, it is impossible to stop every vessel that passes by. It is time-consuming and the legitimate vessels would not like to be stopped because they want to deliver their cargoes in time."
