Police and Crime Commissioners will be elected in November in police force areas across the country to replace little-known police authorities.
Commissioners will control the police budget and have the power to hire and fire the chief constable, who will continue to run operational policing.
A primary election allows anyone to vote, regardless of party membership.
Richard Peek, chairman of the Conservative organising committee, said: "Only Conservatives involve the public in choosing their candidates, and as this proved so successful in selecting candidates such as (MPs) Sarah Wollaston in Totnes and Sarah Newton in Truro and Falmouth, who have proved themselves as excellent constituency MPs, we decided that this was the best method to select our first Police and Crime Commissioner candidate."
Labour last week announced Plymouth councillor Nicky Williams had been selected by party members in the two counties to run in November's vote for a US-style police figurehead in the Westcountry.
The Conservative Party has selected three candidates to contest to be the party's nominee in elections to be Devon and Cornwall's first elected police commissioner.
Former soldier Paul Biddle, Torbay Council's Alison Hernandez and ex-RNAS Culdrose boss Tony Hogg will face a run-off in three open "primary" elections held across the two counties.
The Liberal Democrats have yet to release details of anyone in the frame for the £85,000-a-year post, but have indicated they will stand a candidate in Devon and Cornwall.
The first primary will be held at Westpoint Arena near Exeter on Thursday, July 5, and the second at Kingsley Village, near Fraddon in Mid Cornwall, on Friday, July 6. The final primary, where the result will be announced, is being held on Saturday, July 7, at the Future Hotel on Plymouth International Business Park.
Electors must register to attend by telephone on 01395 233503 or via the website www.policeselection.co.uk.
Mr Biddle is an international security expert with over 27 years' experience in criminal justice. His career began in the Armed Forces and he joined the Prison Service in 1985, working at Brixton, Dartmoor and Portland.
Councillor Hernandez has set up and run her own business and now works as a business improvement consultant for an international firm. She was recently named "online councillor of the year" by the Local Government Information Unit.
Mr Hogg was commanding officer of Royal Naval Air Station Culdrose, managing 3,000 personnel. His naval career included training at Dartmouth and five ship commands.