Waves break along Cenang Beach as the sun drops over the Andaman Sea, washing Langkawi’s white sand in gold. Tourists sip fresh coconuts beneath rows of bright umbrellas, gazing out at the “Jewel of Kedah”: a duty-free archipelago long sold as one of Malaysia’s premier tropical escapes.

Out on the water, meanwhile, small boats traverse the 8km (five miles) of open water that separates Langkawi from Thailand’s Koh Tarutao. On fast boats, the crossing takes a matter of minutes. No navigation lights. No transponders. In the dark, in the right conditions, they might as well be invisible.

Langkawi, an archipelago comprising one main island and around 98 others filled with secluded coves and mangrove-fringed coastlines, has been a tourist magnet for years. But that same seductive geography also makes it a haven for smugglers.

“The sea has become an alternative route for criminals to smuggle illegal migrants, contraband and other items that violate Malaysian law,” First Admiral Romli Mustafa told This Week in Asia aboard the KM Tenggol, one of a number of coastguard vessels patrolling these waters.

Romli heads maritime enforcement for Kedah and Perlis, the two states whose coastlines bear the brunt of maritime smuggling in northern Malaysia.

“The biggest challenge is fast boats moving in the dark,” he said. “Without any information, the chances of us intercepting them are very slim.”

Officials from the Malaysian Maritime Enforcement Agency (MMEA), the Southeast Asian nation’s coastguard, have intercepted methamphetamine and cannabis moving south from Thailand into Malaysia.

Kratom and illegal vapes have been detected heading north in the opposite direction, while subsidised Malaysian petrol, up to 2 ringgit (50 US cents) per litre cheaper than across the border, is loaded onto small vessels in large volumes.

“If they sell 10,000 to 20,000 litres, it is a good activity to make easy money,” Romli said.

But the suppliers and receivers who orchestrate such shipments are rarely the ones detained.

“The fishermen that we arrest only carry out the transporting,” Romli said. “The transaction is made before the fuel is moved.”

As enforcement has tightened along Malaysia’s overland border with Thailand, criminals have increasingly turned to the sea, according to Kedah police chief Adzli Abu Shah.

His officers previously identified 17 strategic entry points in Langkawi and along the coastline of the Malaysian peninsula where smuggling syndicates had established preferred landing routes. But as soon as police patrols increased, the criminals moved on.

Malaysian federal police carried out 231 raids and made 191 arrests between April 10 and May 10 to break up a drug-trafficking ring operating out of Langkawi, officers announced last month.

Kedah’s chief minister, Muhammad Sanusi Md Nor, reacted with a statement to local media describing Langkawi as a drug-trafficking hub and urging “extreme” police action against criminals.

“They drop drugs at sea and people come in boats to collect and distribute them,” Sanusi said. “I ask the police to eradicate Langkawi’s status as a transit point.”

Then there are the people smugglers. Since 2020, 1,333 undocumented immigrants have been intercepted attempting to enter Malaysia via Langkawi and Kedah waters. These interceptions spanned nine separate cases, resulting in the detention of 24 boat skippers and crew members, according to MMEA data.

Last year alone, 436 migrants were detained in two separate mass arrests off the northern coast of Langkawi. In November, a migrant boat capsized off the island’s coast, leaving more than 30 people dead and 14 rescued by Malaysian and Thai officials.

Natural ‘blind spots’

Langkawi’s scattered geography lends itself to maritime crime.

Hidden coves make for perfect hiding spots, while the area’s complex coastlines provide easy escape routes for traffickers to evade border patrols. Small boats can turn off trackers, quickly alter course, secretly unload cargo to another vessel or pull up to a random, empty beach to hide what they are doing.

Smugglers also exploit enforcement gaps created by “fragmented jurisdiction among marine police, customs, immigration and maritime agencies”, according to Sundramoorthy Pathman, a criminologist and policy research expert at the University of Science, Malaysia.

He compared taking down maritime criminal networks to dismantling a decentralised gig economy, what with their rotating rosters of different specialists typically operating semi-independently to handle the transport, storage and bribes involved.

“Over time, some communities may normalise these activities, especially where economic opportunities are limited and informal maritime trade supports local livelihoods,” he said.

Sundramoorthy said Langkawi’s bustling maritime traffic, from tourism to fishing and trade, offered the ideal cover for illicit activity. He described it as an “opportunity structure” in which weak guardianship, economic incentives and high mobility converged to create near-optimal conditions for crime.

Langkawi was chosen by traffickers not just for its proximity to Thailand but also for its combination of open sea access, limited surveillance and local handlers with intimate knowledge of the terrain, said maritime security specialist Nazery Khalid, an adjunct professor at the University of Malaysia, Terengganu

Nazery said criminals exploited “blind spots” in surveillance to build informal landing jetties along narrow, complex river channels that were far harder to detect than arrivals at major ports.

“Such hidden jetties … serve as discreet entry points for the smuggling of contraband and trafficking of migrants,” he said.

“This, combined with limited surveillance systems and a shortage of assets at sea, creates gaps that enable smuggling syndicates to exploit.”

Malaysia’s navy and coastguard both maintain bases on Langkawi’s main island, but Nazery said it was not monitored to the same standard as major port areas such as those at Klang or Tanjung Pelepas.

A 24-hour radar and sensor network used to monitor vessel movements known as the Malaysian Sea Surveillance System does cover Langkawi.

But Nazery said “a more refined” system was needed to better detect “smaller vessels, routes and movements more effectively”.

Insiders or outsiders?

Fauzi Mohammed Nor has run a stall by the fisherman’s jetty at Cenang for years. He is 54 and speaks about the smuggling networks with the matter-of-fact clarity of someone who has simply watched long enough.

“They look for places where there are no people,” he said. “They observe when enforcement officers are on duty. When the area is clear, they come in late at night, sometimes near dawn.”

Fauzi is careful to distinguish between those committing crimes and the fishing community that he knows. For Cenang and Temoyong, he says, involvement is essentially nil. He knows the fishermen there. Other areas, less so.

Langkawi’s fishing association echoed that position. Its president Mahazhir Ibrahim said the organisation had received no reports of members being involved in criminal activity, adding that of more than 4,000 registered members, only around 1,000 were actively fishing open waters in small boats.

The people using the coastline for smuggling were not from around there, he insisted.

“Langkawi is close to the border, those who are doing it aren’t locals,” Mahazhir said. “The foreigners are coming in and using our waters to carry out crimes.”

Authorities are less certain. Romli said local fishermen and boatmen were regularly used as paid carriers, conducting transactions arranged elsewhere.

Adzli added that intelligence suggested local involvement in guiding smugglers to the right landing points at the right times.

“The challenge is identifying the locals involved,” he said.

For maritime security analysts, the longer view is more troubling still. Criminal groups that establish reliable coastal routes do not simply disappear when disrupted, they adapt and over time can create conditions for more serious trafficking. In weapons. In people.

“Sustainable economic alternatives for vulnerable coastal communities are imperative,” Sundramoorthy said. Enforcement alone, without addressing the economic pull that attracts locals to take part, solves only part of the problem.

By nightfall, the beach umbrellas along Cenang are folded and stacked, as the sea darkens beyond the resort lights. Meanwhile, somewhere out on the horizon – past the tour boats and the tourist photographs – the water is moving, and not all of what is there has been accounted for.

This Week in Asia has reached out to Thai authorities for comment.