Anti-knife crime charity the Ben Kinsella Trust said the high proportion of first time offenders is a "red flag", showing more investment into preventative measures is needed.
Ministry of Justice figures show 199 first-time knife crime offenders in Devon and Cornwall went through the criminal justice system in the year ending September 2023.
They accounted for 72% of the total 277 criminals found guilty of knife and offensive weapon offences – up from 71% the year before.
But across England and Wales, the proportion of first-time offenders for a knife and offensive weapon offences fell slightly from 70% in 2022 to 69% last year.
It was the lowest proportion of first-time offenders recorded over the past decade.
Patrick Green, chief executive of the Ben Kinsella Trust, said the high rate of first-time offenders reflects a need for "urgent action and a shift in focus".
He added: "While all knife crime is unacceptable, the high proportion of first-time offenders is a red flag. It exposes a cycle where people are often drawn into violence and face potentially life-altering consequences.
"This is not just a criminal justice issue, but a societal one demanding a multifaceted response."
The figures also show 17% of knife crime offenders in England and Wales last year were under 18 years old.
Of the offenders dealt with by Devon and Cornwall Police, 33 were children (12%).
Mr Green said: "Young people are particularly vulnerable to the allure of knife crime due to complex factors like poverty, lack of opportunity, social media and exposure to violence."
"Simply arresting our way out of this crisis is not enough. We need to invest in preventative measures that address these root causes," he added.
Overall, 29% of knife crime offenders in Devon and Cornwall were given an immediate sentence while 19% received a suspended sentence.
About 21% of them were given community sentences and 17% were cautioned.
A Home Office spokesperson said the number of hospital admissions for young people with serious knife injuries has fallen in recent years, but added more needs to be done to "address the root causes of this violence".
They said: "We have banned zombie and cyclone knives and are going further to stop more zombie-style machetes from being used on our streets.
"We are also investing a further £200 million into the Youth Endowment Fund, and our Violence Reduction units, in combination with Grip hotspot policing patrols, have prevented an estimated 3,220 hospital admissions for violent injuries since 2019."