The Overseas Highway connecting Miami to Key West is one of the most unusual drives in the US — a single road hopping between islands via 42 bridges, with open ocean on both sides for long stretches.
The full drive takes around three and a half hours without stops, but most people spread it over a full day or two, breaking in Islamorada or Marathon along the way.
The Seven Mile Bridge, roughly the midpoint, is the most photographed stretch — worth timing for sunset if your schedule allows it.
Traffic can back up significantly during peak season, so an early morning departure from Miami avoids most of the congestion.