Think of the kids. A visit to Sydney will have consequences. Most will be positive. Australia’s biggest city offers a wealth of transformational experiences. Young minds will be inspired by the spectacular harbor setting, by the laid-back lifestyle and by the weird and wonderful flora and fauna. But there is a flipside. Impressionable children could easily end up talking Strine.

It might be a few stray words at first. Bonzer. Ripper. Corker. Beaut. Gradually, insidiously, new patterns infect their speech. Every sentence they utter will appear to have a question mark at the end of it (linguists call it AQI — Australian questioning intonation). The syllables of individual words will start to merge. When they say “Strine” when they mean “Australian,” the process will be complete. They will have acquired a new dialect.

Full infection takes months. On a short visit, they are likely to pick up a few temporary symptoms. It is a price worth paying for a vacation in one of the greatest cities on Earth.

Sydney enfolds the shores of Port Jackson, an extensive, azure inlet that reaches 11 miles inland. This sheltered natural harbor is vital for trade, transport and recreation and is the obvious starting point for tourists.

Circular Quay, in the shadow of the iconic Opera House, is the downtown ferry terminal. An extensive route network takes in 39 destinations around the harbor, which can be visited cost-effectively with a MyMulti Weekly Pass on Sydney Ferries: Adults pay $36 for unlimited journeys on bus and ferry for seven days; passes for children under 15 cost $18; children under 4 travel free.

You’ll probably want to take things easy on your first day Down Under. Manly Beach, reached by a scenic 30-minute ferry ride from Circular Quay, is the perfect place to shake off jetlag.

The suburb of Manly is situated at North Head, at the entrance to Sydney Harbour. The ferry arrives at Manly Wharf on the sheltered harbor side, from where it is a brief walk along a pedestrian street to a beautiful swathe of sand fringed on one side by Pacific breakers and on the other by all the facilities you are likely to need for the day: cafés, surfboard rental stores and beachwear shops. Be sure to allow an hour or two to visit Oceanworld Manly, an excellent aquarium which offers visitors over the age of 14 the chance to scuba dive in the main shark tank. It is a vivid way to learn that not all shark species are dangerous.

One of Sydney’s most popular attractions, Taronga Zoo, is situated on the north side of the harbor, just a short ferry hop from downtown. The zoo has a large collection of Australian wildlife and is also involved in important captive breeding programs for endangered species from all corners of the globe. The giraffe enclosure is especially photogenic, with the Opera House and the skyscrapers of the Central Business District providing the backdrop.

For much closer encounters with the native marsupials, it is worth making the 45-minute drive from downtown to Featherdale Wildlife Park, a small fragment of wilderness in the western suburbs. Here you’ll not only have the opportunity to see kangaroos, wallabies, koalas and wombats in a natural setting but also to stroke and hold them.

Having been up close and personal with the indigenous critters, you might like to do the same with one of the city’s most famous landmarks, Sydney Harbour Bridge, fondly known as “the coat hanger.” Guided climbs to the very top of the bridge, 439 feet above the water, are available day and night. Climbers must be at least 10 years old and taller than 4 feet. The other great landmark, Sydney Opera House, regularly stages performances specifically for children, including, throughout 2010, the Kids at the House festival. Festival events will include “babies’ proms,” aimed at the under-5 age group, as well as a host of shows for older children.

If your head for heights has survived the bridge climb, then it is well worth taking the express elevator up to the top of the city’s tallest building, Sydney Tower. There are spectacular 360-degree views from the observation deck, and for the truly adventurous there is a vertigo-inducing outdoor skywalk on a glass-floored viewing platform 880 feet above the Central Business District. The minimum age for skywalkers is 10.

Back at ground level, cross the road from Sydney Tower to the monorail station, from where you can catch a train for the short ride to Darling Harbour, one of the city’s premier entertainment and shopping districts. Formerly a working port, the area was redeveloped in the 1980s and offers a wealth of family attractions.

The kid-friendly Australian National Maritime Museum preserves the maritime tradition that was so vital in establishing modern Australia. Exhibits include a full-scale replica of Captain Cook’s ship Endeavour, a 1960s Australian navy submarine and an 1874 tall ship, the James Craig. Family Fun Sundays are held throughout the school term, with a range of special activities for children between the ages of 5 and 12.

At the southern end of Darling Harbour, the IMAX Theatre Sydney boasts the world’s largest IMAX screen. Tickets can be booked online. A short walk from the cinema is the Powerhouse Museum, occupying a former power station. The museum has a diverse collection of hands-on exhibits devoted to technology and design.

Modern Sydney is far removed from its dismal beginnings as a penal colony. Yet beneath the beauty and dynamism of today’s city, vestiges of that history remain. Fourteen of the most important sites are run as museums by the Historic Houses Trust. Of these, the Justice & Police Museum is great fun for children with a particular fascination for the macabre. Here they will be led through the old magistrate’s court and the police cells and will find out about notorious local crimes such as the Shark Arm Murder.

Most trips to Sydney inevitably revolve around the harbor. You will come back to it time and again, strolling the paths along the shore, crossing the bridge and taking to the water. While the ferries provide practical transport between various parts of the city, there is no better way to savor the romance of this famous waterway than on a tall ship.

Sydney Harbour Tall Ships runs daily lunchtime and sundown cruises, and on selected Sundays offers a Family Pirate BBQ Lunch Experience. All family members are invited to dress up as pirates for the two-hour voyage, departing from The Rocks in the shadow of the Harbour Bridge.

Tacking across Sydney Harbour in a tall ship under full sail — whether you are dressed as a pirate or not — is an unforgettable experience. Fortunately, the local lingo provides a rich vocabulary by which to exclaim approving wonder: Bonzer. Ripper. Corker. Beaut.

Info To Go

International passengers arrive at Sydney Airport (SYD), six miles south of the city center. A taxi from the airport to downtown costs about $22. The Airport Link train service departs every 10 minutes and takes 13 minutes to reach downtown; $9 for adults and $6.70 for children.

Lodging

BLUE Sydney
Thirty-six of the hotel’s 100 guestrooms are lofts with separate sleeping and living areas. Its Wharf at Woolloomooloo location is convenient to Sydney’s business and shopping districts. 6 Cowper Wharf Road, tel 61 2 9331 9000 $$$$

Park Hyatt Sydney
Amenities for children are limited, but all that Sydney has to offer is on your doorstep in this harborside location. 7 Hickson Road, The Rocks, tel 61 2 9256 1234 $$$$

Rydges World Square
Rydges is very family-friendly, offering adjoining rooms, many with kitchenettes. The property is within walking distance of Darling Harbour and the CBD. 389 Pitt St., tel 61 2 8268 1888 $$

Dining

Harry’s Café de Wheels
Harry Edwards opened a mobile café at Sydney’s naval dockyard in 1938. The café still serves the ultimate meat pies and mushy peas. Cowper Wharf Roadway, Woolloomooloo, tel 61 2 9357 3074, $

Lindt Chocolate Café
The sandwiches are everything you could wish for, but they are just the opening act. What you really come here for is everything chocolate. 53 Martin Place, tel 61 2 8257 1600 $$

Saké
Great seafood and Asian cuisine are Sydney staples. This trendy sushi eatery combines the two and offers an inventive kids’ menu. 12 Argyle St., The Rocks, tel 61 2 9259 5656 $$$