Florida is a closed primary state. This means you can only vote in a partisan primary election for the candidates of the party in which you are registered. All registered voters, regardless of party affiliation may vote in nonpartisan races and on issues.
If all candidates in a primary race have the same party affiliation and the winner will have no opposition in the general election, all qualified electors, regardless of party affiliation, may vote in the primary election for that office. This is called a universal primary contest.
Note: Party changes must be made by the 29th day before an election.