10 men have been jailed for conspiracy to supply class A drugs across West Wales - they were handed 54 years between them.
On Thursday, eight men were jailed for a total of 66 years at Swansea Crown Court.
Operation Ulysses disrupted the supply of heroin, cocaine, ketamine and cannabis. It was one of the biggest and most complex cases for the Serious and Organised Crime Team at Dyfed-Powys Police.
A further 10 people are due to be sentenced in connection with this on Monday and Tuesday.
The ten defendants who were sentenced on Friday in Swansea Crown Court were:
Christopher Twist – 6 years 8 months
Jody Moore – 4 years 8 months
Ashley Mercer – 5 years 4 months
Hardev Singh – 5 years
Jarod Jones 4 years 6 months
Declan Williams – 8 years
Christopher Morris – 8 years
James Wright – 3 years 6 months
Seorse Bailey – 4 years 4 months
Sam James – 4 years
The eight defendants who were sentenced on Thursday in Swansea Crown Court were:
Ryan Kenny - 14 years
John Kenny - 4 years 4 months
Matthew Baldock - 6 years
Michael Lewis - 6 years
Christopher Inglesby - 13 years
Howard Jones - 6 years 8 months
Gerwyn Bailey - 8 years
Max Hampson - 8 years
Detective Sergeant Rhys Jones, from the Dyfed-Powys Police Serious and Organised Crime Team, said: "We are extremely pleased with the sentences handed to all 8 defendants today, particularly the 14 years handed to Ryan Kenny, on this the first day of sentencing 28 individuals as part of Operation Ulysses.
"The operation was commenced as a result of an increase in the number of heroin related deaths predominantly in the Llanelli area, and these sentences are the successful culmination of the most complex investigation undertaken by the Serious and Organised Crime Team, resulting in putting these first eight members of sophisticated organised crime groups behind bars for a considerable time.
"The investigation and deployments of officers spanned Carmarthenshire, Ceredigion, North Wales and Liverpool, and extremely large amounts of heroin, cocaine, ketamine and cannabis were seized. These defendants operated covertly and executed their criminal enterprise with precision.
"The amounts involved are staggering in terms of the drugs that were distributed onto and flooded the streets of Aberystwyth and Llanelli. Operation Ulysses has tackled the scourge of these drugs and helped prevent further tragedies.
"This first batch of sentences just goes to show that no matter how sophisticated these organised crime groups are, Dyfed-Powys Police will find them and bring them to justice.
"We wait with anticipation to hear the sentences handed to the remaining 20 defendants over the next three days in court."
Superintendent Gary Mills, Carmarthenshire Divisional Commander added: "As well as pursuing those organised crime groups that were conspiring to supply Class A drugs in our communities, we were acutely aware of the effect the disruption of supply to users of Class A drugs that this action would result in.
"From the outset we worked very closely with our partners in health and drugs charities to ensure the appropriate support was, and continues to be available to them.
"Local policing have and will continue to work with partners throughout this operation including Local Authorities to support our communities and individuals most affected by serious and organised crime.
"We urged users of Class A drugs to seek the help and support that was available to them. Our partners were ready and waiting to provide them with all the necessary help that they required - and we stressed how important it was that users took advantage of this opportunity.
"Together with our partners, our priority was to give them the chance to turn things around, and live a drug free life. But we were also clear that if they did not engage in the treatment and support being offered, continued drugs use would not be tolerated in the Dyfed-Powys area.
"We have seen too many lives end in tragedy, and the suffering that families and friends have to endure. These sentences send out a clear message that the Dyfed-Powys Police force area remains a hostile environment for those involved in serious and organised crime at all levels."