Key West has a well-earned reputation as an adult playground. The section of Duval Street closest to the cruise ship docks is packed with popular bars and has been likened to Bourbon Street in New Orleans for its laissez les bons temps roule (Let the good times roll!) attitude. But keep in mind that this is just one small slice of the island. Key West is also full of family-friendly activities, all within easy reach. 
The Conch Tour Train — Photo courtesy of Bob Krist / Florida Keys News Bureau
Get off to an early start by booking the first Conch Tour Train ride of the day through your cruise line, and the train will actually pick you up at the ship once you’ve docked. They condense the normally 90-minute tour into one hour for cruise passengers, which is perfect for children with a limited attention span. The Conch Train is an easy way to get acquainted with the entire island and its history.
Their knowledgeable “engineers” will give you an overview of the historic district, covering 100 points of interest, such as the Ernest Hemingway House, Southernmost Point, the conch-style architecture and more. They also provide an entertaining commentary on the legends of the city like Robert the Haunted Doll, who lives at Fort East Martello. Added bonus: kids under 12 ride for free.
Once you get off the train in Mallory Square, you’ll spot the Key West Aquarium, with a distinctive great white shark bursting from the top of its façade. Built between 1932 and 1934, it’s one of Florida's oldest aquariums. While on the small side, the facility offers children the opportunity to touch and hold living starfish, sea cucumbers, horseshoe crabs and conches. 
Touch tank at the Key West Aquarium. — Photo courtesy of Kathryn Watkins
The long building is lined with tanks that showcase the other critters that populate the Florida Keys, like eels, lobster, seahorses and glowing jellyfish. You’ll also spot alligators, stingrays and rescued sea turtles on view. Catch one of the tours for a chance to feel the skin of a juvenile nurse shark and watch the frenzy at feeding time.
Next up, it’s time for an outdoor adventure at Fort Zachary Taylor State Park. The park is a little over a mile away from Mallory Square, so you have a few options for getting there. You can make the 30-minute walk, rent a bicycle from Eaton Bikes (It’s about a 10-minute bike ride.) or call Five Sixes Taxi and load your brood into one of their pink SUV's.
Once you arrive at the 54-acre park, head to the secluded beach and hit up the concession stand for a picnic lunch. They offer kid-friendly hamburgers and hotdogs, as well as adult-friendly sandwiches, wine and beer.
Rent some snorkel equipment and wade out into the clear shallow waters to get up close and personal with the rich tropical marine life: parrot fish, yellowtail snapper, lobster and corals. Wear water shoes or flip flops, as the sand can be a bit rocky.
After you’ve enjoyed a refreshing dip, go explore the Civil War-era fort. The kids will love seeing the huge canons and climbing to the top of the three-story brick structure for panoramic views of the island.
Beach at Fort Zachary Taylor State Park — Photo courtesy of Fred Peche