Currently there are no COVID testing requirements or quarantine for domestic travel into Florida. More information can be found for Marco Island specifically at the link below. https://www.cityofmarcoisland.com/emergency/page/covid-19-coronavirus-information
The state of Florida entered phase 3 on September 25, 2020 meaning that all businesses and restaurants are able to run at full capacity. However, most businesses including the resort have social distancing practices and extra cleaning procedures in place. The county commissioner passed a mask mandate, but it is expected to expire on April 13, 2021.