Craig Mackinlay, Nathan Gray, and Marion Little have been charged with offences under the Representation of the People Act 1983.
Mackinlay, his agent Nathan Gray, and Marion Little – a former Conservative party strategist and organiser, 62 – have been charged with offences under the Representation of the People Act 1983.
The allegations were first revealed by a year-long Channel 4 News investigation.
Craig Mackinlay narrowly beat Nigel Farage, the former Ukip leader, in the 2015 general election to become MP for South Thanet.
Craig Mackinlay will remain on the ballot paper for the general election.
Nick Vamos, CPS Head of Special Crime, said: “On 18 April we received a file of evidence from Kent Police concerning allegations relating to Conservative Party expenditure during the 2015 General Election campaign.
“We then asked for additional enquiries to be made in advance of the 11 June statutory time limit by when any charges needed to be authorised.
“Those enquiries have now been completed and we have considered the evidence in accordance with the Code for Crown Prosecutors.
“We have concluded there is sufficient evidence and it is in the public interest to authorise charges against three people.”
The three people are due to appear at Westminster Magistrates’ Court on 4 July 2017.
The three could face trial in the Crown Court.
The maximum sentence is one year in prison or a fine.
Police forces have been investigating whether election expenses were filed correctly under national expenses – or whether they should have been filed locally.
The Conservative party said: “The legal authorities have previously cleared Conservative candidates who faced numerous politically motivated and unfounded complaints over the Party’s national Battlebus campaigning.
“We continue to believe that this remaining allegation is unfounded. Our candidate has made clear that there was no intention by him or his campaigners to engage in any inappropriate activity. We believe that they have done nothing wrong, and we are confident that this will be proven as the matter progresses.”
Last month the CPS said that it would not bring charges against any other Conservative MPs or officials over allegations of spending irregularities in the 2015 campaign.
Files from 14 police forces were considered by Crown Prosecutors. It was determined by the CPS that spending returns may have been inaccurate but there was insufficient evidence to prove that any candidate or agent was dishonest.
Those investigations focused on claims that expenses for transporting Conservative activists in so-called Battlebuses and sent to key seats were wrongly reported as part of the party’s national spending than in the candidates’ local returns.