Traffickers are avoiding the roads when they deliver drugs these days with Covid-19 checkpoints now commonplace on the roads, according to the Central Investigation Bureau (CIB).
Fast-spreading infections have been met with lockdowns and curfews in heavily-affected provinces where authorities regulate the flow of people and goods in and out of provinces.
Public health surveillance and security checkpoints are up and running on many roads to screen motorists, and the presence of law enforcement has unnerved drug traffickers.
They are taking a different course to elude the police by loading their drugs onto a boat and shuttling them to spots close to the border with Malaysia where the supplies are then collected by a local agent who exports them to a third country.
Marine police based in Satun recently teamed up with Border Patrol Police (BPP) officers to nab a large group of fishermen trying to smuggle out of the country a large quantity of crystal methamphetamine or "ya ice".
It was the first time the police have found illicit drug consignments equipped with an advanced GPS tracking system.
CIB commissioner Torsak Sukwimol said more networks of transnational drug traffickers are opting to transport drugs by sea in recent months to evade authorities.
The highways and roads are unappealing given the presence of road blocks.
Police discovered Satun provides a popular transit point for drug smugglers, given the province's easy access and close proximity to Malaysia.
"I've ordered the marine police to do a regular patrol of the waters. They stop for a search any vessels suspected of containing illicit cargo," said the commissioner.
However, Pol Lt Gen Torsak said pursuing traffickers by boat is no easy task as the vast expanse of the sea gives suspects a lot of room to get away.
The police rely on informants to scour intelligence before organising sting operations. This requires integrating the work of the BPP, anti-narcotic and local police units.
Police employ moles who infiltrate drug trafficking rings, he said.
He added the gangs have installed GPS devices in large batches of drugs, which guide the gangs to precise meetings and drug pick-up locations in the Andaman Sea.
The gangs rarely use mobile phones or radio transmitters because they can be tracked.
Pol Lt Gen Torsak said police have come across heroin among the narcotics trafficked across the border. The drug is back on the market after a phase in which demand had dwindled.
The economic slump has now driven more people to join drug smuggling networks which also involve the trafficking of humans, according to the commissioner.
In June, the Marine Police Division 9 (MPD9) seized ya ice and heroin worth at least 500 million baht in a swoop.
On July 27, the Marine Police sent a patrol boat to intercept a fishing trawler named Kor Niyomsin along the Thai-Malaysian sea border near the Malaysian resort island of Langkawi.
Police nabbed a man identified only as Tee, a native of Satun, in the boat which was carrying 30kg of ya ice worth six million baht contained in two sacks.
Marine Police commander Pol Maj Gen Somkwan Puengsap said police have stepped up sea patrols to catch the gangs despite the monsoon season.
Pol Col Jaturawit Kotchanuam, superintendent at the MPD9 with marine jurisdiction in Satun, Trang and Krabi, said June to September marks the peak period for delivery of illicit drugs along the Andaman Sea coast.
The drugs are brought to Satun by car or train and sent out on small or medium-sized fishing boats heading to the maritime border. The fishing boats are moored in shallow water along mangrove forests which large police patrol vessels cannot reach.
The gangs often brought the drugs on boats along the shores of Ban Klong Yaek where there is no mobile phone reception in Palian district of Trang. The locations can help them evade police tracking.
Contact Crime Track: crimetrack@bangkokpost.co.th