In a statement, the Crown Prosecution Service said that Mackinlay, 50, Marion Little, 62, and Nathan Gray, 28, had have each been charged with offences under the Representation of the People Act 1983.
They are due to appear at Westminster Magistrates' Court on July 4.
Mackinlay was elected as MP for South Thanet in 2015 beating Mr Farage - the then Ukip leader - into second place and is the Conservative candidate for the Kent constituency in this year's election.
A spokesman for Mackinlay declined to comment but a Conservative Party spokesman said they believed the allegation against him was "unfounded".
"The legal authorities have previously cleared Conservative candidates who faced numerous politically motivated and unfounded complaints over the party's national battlebus campaigning," the spokesman said.
"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.
"The individuals remain innocent unless otherwise proven guilty in a court of law. The press, parties and those on social media should be aware of the provisions of the Contempt of Court Act and the strict liability rules against publishing anything which would prejudice the course of justice.
"There is a broad consensus that election law is fragmented, confused and unclear, with two different sets of legislation, and poor guidance from the Electoral Commission.
"Conservatives are committed to strengthening electoral law to tackle the real and proven cases of corruption that were exposed in Tower Hamlets in 2015."