T-Mobile, AT&T, and Verizon all deploy 5G extending across the downtown core, Miami Beach, and major suburbs. South Beach, Ocean Drive, Collins Avenue, and Lincoln Road Mall all have excellent outdoor signal. Brickell, Downtown Miami, Edgewater, and Midtown have strong 5G.
Wynwood's art district, Little Havana along Calle Ocho, and Coral Gables' Miracle Mile are fully covered. The Port of Miami cruise terminals have 4G in the passenger areas. Miami International Airport has full coverage across all concourses.
The Metrorail and Metromover systems have surface coverage along most of the route. The Florida Everglades to the west and southwest of Miami have very limited coverage. Keep that in mind if you plan an airboat tour or drive the Tamiami Trail.