No. Florida law does not require witnesses to be present for a marriage ceremony.

The couple must have a valid Florida marriage license and the marriage must be solemnized by a person authorized under Florida law, such as a Florida Notary Public or qualifying clergy. Online Sunshine

You are welcome to have family members or friends present for your ceremony, but witnesses are not required for the marriage to be performed.

Florida law does reference two witnesses in a separate situation where a marriage needs to be proven by affidavit because the proper marriage certificate is unavailable, but that is not a requirement to have two witnesses at an ordinary Florida wedding ceremony.