Bills have been introduced in each house of the Florida legislature to amend the oath of office that newly-elected legislators take at the beginning of a legislative session. The bills provide that the oath should be expanded to say that the legislator acknowledges that the National Popular Vote Plan would be illegal. Here is the text. The bills are SR 1458, by Senator Dennis Baxley (R-Ocala); and HR 323, by Representative Bob Rommel (R-Naples).
In the meantime, bills for Florida to join the National Popular Plan have been introduced in both houses. They are HB 335 and SB 908.