Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Bangkok to Florianopolis as you normally would.
Located just 7.8 km from the city centre, Florianopolis Hercilio Luz is the airport most travellers will use when flying to Florianopolis from Bangkok. Booking flights from Bangkok to Hercilio Luz (FLN) should be relatively easy as there are 0 daily inbound flights from Bangkok from 0 different airlines.