Police swooped on drug dealers supplying users who were waiting for a delivery.
One of the men had come from London to deal heroin and crack cocaine, and the other was a local contact who knew the area.
A judge said the case highlighted the way criminal gangs from big cities are operating in smaller towns and cities.
Both men have been locked up, with the judge warning that those who continue to peddle Class A drugs can expect the same.
John Hipkin, prosecuting, told Swansea Crown Court that on October 2 this year police involved in a drugs operation stopped a black Ford Focus car at the junction of Heathfield and Carlton Terrace in the Mount Pleasant area of the city.
Nearby a number of known drug users had gathered, seemingly awaiting a delivery.
Officers spoke to London teenager Ahmed Hassan and Swansea man Ben Alley who was at the wheel of the car.
The court heard the plain clothes officers searched the pair, and Hassan was found to have 15 wraps of heroin and 15 wraps of cocaine. A mobile phone was seized from the car, which showed contact with members of an organised criminal gang in London.
Hassan, 19, of Whitton Avenue West, Northolt, London, and Alley, 28, of Bryn Road, Loughor , had previously pleaded guilty to possession of heroin with intent to supply and possession of crack cocaine with intent to supply when they appeared in the dock for sentencing. Alley had also previously pleaded guilty to driving while disqualified.
The court heard Hassan had been a university student who became involved in Class A drug trafficking after running up a £250 cannabis debt to dealers in London, while Alley had worked for a security firm and been a "responsible member of society" before becoming addicted to drugs and falling prey to dealers.
Judge Geraint Walters said Hassan had been running drugs from London to Swansea, and that Alley had been using his local knowledge and contacts to help.
The judge said criminal gangs from big cities such as London were targeting places like Swansea, and as a result the city was seeing an "ever increasing number" of drug-related deaths.
Addressing the pair, he said: "It is a welcome sign that police forces here are targeting, and rightly so, people like you.
"Conduct of the like you were engaged in ruins the lives of others - it ruins the lives of pathetic users and causes them long-term harm or even death, and it seriously affects communities where decent and honest people have to put up with dealing.
"It is only to be expected that those caught dealing in Class A drugs will be severely punished."
Judge Walters said the way courts dealt with drug dealers was well-known, and that both men had therefore gone about their business "with eyes wide open".
He said it had been "extraordinarily stupid" of Hassan to get involved in Class A dealing over a £250 debt.
Hassan and Alley were both given three-year sentences with Hassan serving his in a young offender institution.
Alley was banned from driving for three months.
