Key West or Savannah?

Neither has a great town beach, and the two offer different kinds of water. Key West's sea is clear, warm all year and calm behind the reef, but the shore is small, either imported sand or coral rubble. Most of the time goes on snorkelling and boats, and a proper sandy beach means the hour's drive to Bahia Honda.

Savannah's beach is Tybee Island, half an hour away, with wide flat sand for walking and paddling but greenish, marsh-coloured water that is only warm in summer. Tybee is better for a towel and an umbrella. Key West is better for getting in the water and looking beneath the surface.

Key West eats well but within narrow limits: fresh fish, stone crab in season, Key lime pie and Cuban coffee from takeaway windows. Its best meals are at dockside shacks rather than serious dining rooms, and Duval Street is mostly bar food.

Savannah has more to offer at the table. Lowcountry cooking gives it real dishes to seek out, from shrimp and grits to oyster roasts. It also has family-style dining rooms and a small tier of chef-led restaurants around the historic district and south of Forsyth Park.

In both towns the streets are the main sight, but Savannah has far more to fill the days. Key West's Old Town of conch cottages and Victorian verandas is lovely to wander, and the Hemingway Home, the Little White House and the shipwreck collections tell a lively island story, but two days covers it.

Savannah has Oglethorpe's grid of oak-shaded squares, the Telfair Museums, the Owens-Thomas House with its account of the enslaved people who worked there, and Bonaventure Cemetery. Together they make a richer and more varied run of architecture, art and history.

Key West is the place to stay out late. Duval Street's open-sided bars and rooftop decks run into the small hours, the evening begins with the sunset crowd on Mallory Square, and the gay scene at the upper end of Duval is long established. Stylish cocktail bars and real clubs are scarce, though.

Savannah's to-go cups make for a pleasant drift between River Street, City Market and cocktail rooms in old townhouses. Outside St Patrick's Day, however, the city mostly winds down well before Key West does.

Key West wins for anyone who wants to be on the water or under it. The Florida Reef lies a few kilometres offshore, the backcountry flats suit kayaking and fishing for tarpon and bonefish, and the Dry Tortugas add remote islands and birdwatching. On land there is almost nothing.

Savannah's Lowcountry is gentler: kayaking the salt marsh at high tide, dolphin trips, herons and wood storks, and walks at Wormsloe and Skidaway Island. It is pleasant in spring and autumn, but there is no reef, and summer insects and humidity keep outings short.

Key West sits at the end of the road. Beyond the ferry to Fort Jefferson in the Dry Tortugas, the choices are small Keys towns such as Marathon and Islamorada, and the Seven Mile Bridge is the best part of the drive.

Savannah is a far better base. Charleston is about two hours north, Beaufort and Hilton Head are an hour or less away, Fort Pulaski fills a half day, and Jekyll and St Simons islands lie to the south. Nearly all of these need a car.

Neither town is built around children. Key West's appeal for them is mostly on the water: calm shallows at Fort Zachary Taylor, glass-bottom boats and the Tortugas ferry, plus a small aquarium and a butterfly conservatory. Duval Street's early drinking and the adult tone of Fantasy Fest make it the less comfortable fit.

Savannah is the easier choice with children. The squares and Forsyth Park give shade and room to run, and the trolley tours and free river ferry are simple treats. The forts and ghost walks suit older children, and Tybee adds a gentle beach with a sea-turtle centre.

Both centres are flat and compact enough to leave the car behind, but you get around them differently. Key West is a bicycle town, with rental bikes, electric carts and scooters everywhere and all of Old Town a short ride apart. Reaching the rest of the Keys means driving the single highway.

Savannah is explored on foot, square by square across its grid, with a free downtown shuttle and a river ferry to help. Bonaventure, Wormsloe and Tybee lie outside that core and need a car or a tour.

What you bring home differs. Key West's shops are mostly about the island itself: T-shirts and Key lime everything along Duval Street and, more worth your time, Old Town galleries of tropical painting, hand-rolled cigars and the sponge and shell shops by the harbour.

Savannah gives you more to browse. Broughton Street is a real shopping street, with boutiques and home-goods shops in restored storefronts, art school students and graduates sell their work, and antique dealers and bookshops are scattered among the squares. In both towns, though, shopping fits into an evening walk rather than being a reason to come.

Key West is by far the dearer of the two. Building is restricted on the small island, so even a guesthouse in an old conch house costs well above the American norm, and Duval Street charges resort prices for food and drink. What keeps spending down is that you need no car: bikes cover everything, and the fish shacks and Cuban takeaway windows are fair.

Savannah is not cheap either, but the gap shows from the first night, since its inns cost less than Key West's and meals cost the usual Southern amount rather than island prices. The ways to save work in opposite directions. In Key West you save by leaving wheels behind, while Savannah's cheaper rooms are out of the centre and bring a car into the budget. In both, the cheapest time is the hot, stormy summer.

Both offer more informal entertainment than formal culture, but of different kinds. Key West's is nightly and casual: singer-songwriters in the Duval bars, long-running drag cabaret and the street performers at the Mallory Square sunset. The Tennessee Williams Theatre and a winter symphony season cover the seated side.

Savannah's comes in seasons. The Savannah Music Festival brings chamber music, jazz, blues and Americana to theatres and churches each spring, and an autumn jazz festival fills Forsyth Park, but outside those dates there may be little to attend.

Neither has a bathing tradition, and in both the rest comes from the slow pace rather than from spas. Key West offers guesthouses set around small pools and the daily pause for sunset, though the party is never far from Duval. In Savannah, calm means a bench under the oaks or an inn courtyard on a southern square, best midweek in spring or autumn before the summer humidity sets in.