Dinsdale-Dette admitted eight charges, including selling benzylpiperazine (BZP) and cannabis.
Williams pleaded guilty to five charges, including conspiring to sell BZP and selling cannabis.
The two were represented by solicitor Ian Hard.
Dinsdale-Dette was working as part of a distribution network for Clint Helmbright, 44, and his partner Jody Turner, 23, alleged to have been at the centre of the drugs syndicate, spanning across the country.
Dinsdale-Dette would purchase BZP-based pills and cannabis from Helmbright using coded talk, referring to a cannabis ounce as a "bottle of rum", "Fiji rum", "tyres", or "mags".
Reference to "cars" and "servicing for cars" was used when talking about BZP.
Between April and October, 2013 Dinsdale-Dette was regularly supplied with cannabis and BZP pills to on-sell.
During this time Dinsdale-Dette lived with Williams, who helped her sell cannabis on several occasions when Dinsdale-Dette was not home.
Every three to four weeks Dinsdale-Dette would receive about 25 BZP pills, paying $25 per pill and then on-selling them for between $40 and $60 each.
She also assisted Helmbright and Turner with their drug dealing enterprise by travelling on their behalf to Christchurch where she exchanged drugs for money and by distributing pills and cannabis throughout Wellington to Helmbright and Turner's associates.
On October 23, a search warrant was executed at Dinsdale-Dette's home, as police entered her home she attempted to run out the back door with 30 pink BZP pills.
When spoken to by police she admitted buying cannabis and BZP pills from Helmbright and Turner, between April and October, 2013, to on-sell.
She said she bought one to three ounces of cannabis every week and 25 BZP pills every few weeks.
Based on her admissions, between April and October, Dinsdale-Dette would have obtained about 250 BZP pills, a street value of about $15,000 and between 27 and 81 ounces of cannabis, worth up to $28,350.
Dinsdale-Dette and Williams will be sentenced in Masterton District Court on April 3.
Judge John Bergseng requested a pre-sentence report and an alcohol and drug report.