The Australian National Maritime Museum is located in Sydney's beautiful Darling Harbour. The sight of the Museum's historic collection of Maritime vessels, each floating in the harbour, has become a stunning aspect of the area's landscape and is well worth a visit. It also makes for some beautiful photos!
All of these vessels can be accessed by the public with a ticket ($30 for adults, $15 for children aged 4-15, and under 4's free), while the Museum's permanent exhibitions can always be accessed for free. I personally found the ticket to be worthwhile, as it gives visitors the opportunity to climb aboard and explore vessels they would not normally ever encounter, and allows visitors to access any special exhibitions currently on show.
The Onslow Submarine is a must-see, illustrating the trying conditions seamen and women experience when travelling on these vessels, the technological development of submarines, and their use in the Cold War. Hearing about the vessel's history from volunteers (who often have Naval experience themselves) is not only incredibly informative, but helps to bring this history to life. If you're at all claustrophobic however, I recommend avoiding this one!
The Museum also constantly offers a variety of exhibitions that cover particularly Australia's Maritime history, but also international maritime history. Exhibits have previously covered the European settlement and charter of Australia, the history of immigration (via boat), pirates, World Wars, Australia's Royal Navy, and Aboriginal and Torres Strait Islander cultures in relation to the ocean. Children's exhibitions are also frequently offered, with special programs usually offered in line with the school holidays.
Make the most of the Museum's beautiful setting and have lunch here! You can eat at the Museum's Yots Cafe, which is harbour facing and has meal deals for kids, or to save some money, you can bring your own lunch and eat at one of the Museum's picnic tables. Both options allow you to take in the beautiful (especially on a sunny day) harbour scenery!
I wouldn't recommend driving here but public transport will take you pretty much to the doorstep. You can get the light rail from Central station straight to the Museum.