Some cartel members have testified about using subways. But no one has said that they have transported drugs to the US on unattended parts of the border.
The testimony comes at a time when President Donald Trump's pressure on a border wall argues that it would help stop the drugs in the United States.
US Border Patrol took nearly 480,000 pounds of drugs at the border between the US and Mexico between the legal ports for entry during the fiscal year 201
From tunnels to legal ports
In Guzman's case, the government's own witnesses – many of the former Mexican cartels – confirmed that after the government burst into smuggling tunnels, they began to rely on legal ports for entry to Get drugs into the country.
The formerly loud Sinaloa cartel leader Jesus Zambada Garcia testified about Guzman's use of tunnels in the early 1990s to quickly smuggle drugs such as cocaine in the United States, earning him the nickname "El Rapido" or "The Fast One".
"A tunnel is the safest way to cross drugs to the US – the easiest way to cross over weapons ons," Zambada Garcia testified.
Zambada Garcia was arrested in Mexico City in 2008 and extradited to the United States, claiming to import, distribute, and sell cocaine and belong to a continuing criminal enterprise. He is not convicted but can face between 10 years and imprisonment.
He said that in the late 1980s to the beginning of the 1990s, 95% of the cocaine was brought into United States through a tunnel under the Arizona border with Mexico However, since law enforcement began to detect and close tunnels, cartel management directed drugs to other parts of the United States
Tractor Trolleys were and continue to be a popular method of drug smuggling. With a "double bottom" that has hidden compartments, others are filled with goods, like large cans of chili, which contain sand that surrounds a specially made cylindrical brick of cocaine. "From about 1990 to 1993, nearly 30 tons of cocaine were smuggled in the United States using this method," said Zambada Garcia.
Vicente Zambada was guilty of drug trafficking costs and is now imprisoned in the United States.  "Mexican families were hired to drive cars with secret compartments across the border at Juarez, sometimes three or four times a day," he said.
It was also a time when Sinaloa employees sent drugs to the US on trains.
In December, Tirso Martinez Sanchez testified that between 2000 and 2003 he was able to smuggle in 30-50 tons of cocaine by welding false compartments at the ends of oil tankers. Martinez testified that he and his associate vacuum-sealed cocaine in bags, wrapped them in plastic, and rubbed them with the mechanic's fat to throw off drug-smashing dogs.
Martinez Sanchez was arrested in February 2014 and extradited to the United States in December 2015. The following year, he pleaded guilty to drug trafficking costs after meeting a cooperation agreement with the government.
According to the cooperation agreement, the government will send a court letter to the judge and help Martinez Sanchez secure an S-visa, a green card issued to witnesses and informants who have assisted in law enforcement. He is currently protected custodian and faces at least 10 years in prison.
Another method that witnesses testified about using involved fishing boats and other vessels. In fact, Guzman himself is believed to have been intercepted to send messages to a woman and ask her to find someone "willing to fish" or meet a ship filled with drugs hundreds of miles from US coastal drugs back to the shore of a fishing boat.
El Chapo on trial
Guzman led the infamous Sinaloa cartel, described by the US Justice Department as one of the world's most violent and powerful drug cartels. He repeatedly broke out of prison until he resumed in January 2016.
Guzman was extradited to the United States and did not plead guilty to 17 federal charges involving the conduct of a continuing criminal enterprise, firearms crimes in drug trafficking and money laundering.
Smuggling of drugs through legal ports is a risky activity. But cartels aimed to limit their losses by sending through large enough quantities that even if some were seized, others would still do so.
This way of thinking was divided into court of former Colombian cartel head Juan Carlos "La Chupeta" Ramirez, who worked with Guzman in the early 1990s and is now in US prison.
Ramirez cartel would grow, process and send cocaine transfers to Mexico by air. Guzman's job was to get the drugs smuggled into the US.
When Guzman quickly completed his methods of smuggling drugs into the United States, Ramirez, through a variety of methods, could not get enough.
He told me to send him as many aircraft as I could. "
Ramirez is in prison in the United States for drug trafficking. He filed a guilty verdict and reached a cooperation agreement.
As part of Ramirez's extradition agreement with Brazil, where he was captured, he should not serve more than 30 years. But if the government's lawyers are happy with Ramirez's cooperation, they may choose to write a letter to a judging judge who can help Ramirez get less time – even if his cooperation agreement stipulates that he may not earn less than 25 years.