Cruse southern Australia Melbourne to Perth

Both Adelaide and Perth, and the countryside surrounding the cities, would be excellent choices for explorations by car. I'd strongly suggest reconsidering any thought of driving thru the Nullarbor Plain between them however - it's a featureless and relentless desert with nothing to recommend it in a car. Even most Aussies would never attempt it. If you feel it's a must see for you then consider the train, otherwise better to rent your car in Melbourne, drive the Great Ocean Road to Adelaide and explore the pretty Barossa Valley before turning in your car and flying Jetstar - the Qantas low cost airline - over to Perth to rent another vehicle for explorations in Western Australia. The seaside suburb of Fremantle is a particular favorite.
Can't comment about an ocean cruise from Melbourne around to Perth.

Might add that a trip to Ayers Rock/Uluru would be a very worthwhile side trip depending on your available time and interests - there's lots to see and do in the vicinity besides the iconic rock.

You won't find many cruises that only sail between Melbourne and Perth (Fremantle). Those cruises that include both, plus Adelaide, will be longer cruises that start and end at much more distant places. The shortest cruises would likely be those that circumnavigate Australia. Have a look at the Cruisetimetables. com websites and input either Melbourne or Fremantle (Perth's cruise port) to see the cruises stopping in either port.

You won't find cruises that only sail between Melbourne and Perth (Fremantle).

Cunard has one - Melbourne to Fremantle cruise.

Thanks Aussie Nomad for finding that. I edited my post. I see now that there is also an Azamara cruise on the Journey that has a 14 nighter in December '23.

thought this might be something to consider. Thoughts...

There's a lot of ocean between Melbourne and Perth and not a lot of ports. Any cruise will likely only stop at Adelaide (nice city, great food and wine) and Albany (small port) before getting to Fremantle. So only a good idea if you really like cruise boats.

A better option would be to drive from Melbourne to Adelaide via the Barossa Valley for excellent wineries then fly to Perth. An easy day trip from Perth is the ferry to Rottnest Island where you will see the unique quokka, a small mammal that looks like a cross between a wallaby and a meerkat.

If you want a quintessential Australian cruising experience then look for one in the Kimberley region leaving from Broome and heading north.

We did a cruise of Australia in 2013 from Perth to Sydney with a stop in Bali as well Aussie cities. It was great.

We enjoyed our three days in Perth, we did one day wine tasting taking a tour on a river boat from Perth. We did a day in Perth and another day in Freemantle, I remember visiting an old prison there, among other things.

I don't think there is much to see between Adelaide and Perth.

We did visit Melbourne later and loved the Great Ocean Highway and the penguins at Philip Island.

We are thinking of doing a whole 35 day circumnavigation cruise in 2024 but you can book the southern part as a separate cruise too on Holland America. https://www.hollandamerica.com/en_US/find-a-cruise.html#%7B!tag=destinationTag%7DdestinationIds=&%7B!tag=departTag%7DdepartDate=&%7B!tag=durationTag%7Dduration=&%7B!tag=embarkTag%7DembarkPortCode=PER&%7B!tag=portsTag%7DportsOfCall=&%7B!tag=shipsTag%7DshipId=&%7B!tag=regionTag%7Dregions=&%7B!tag=cruisetypeTag%7DcruiseType=&soldOut=&start=0

EDIT: You can also request to leave the cruise in Melbourne instead of continuing on to Sydney if that is more convenient for your family visit.

Thankz. The one six-day cruise I looked into was at sea for three days straight. We've never done a cruise, and I think in this case our time would be better spent flying and driving. The 14-day cruise did look interesting. We'd like to visit Tasmania one day too. Driving to and around Adelaide looks good, with a flight to Perth.

My two cents: Tasmania is gorgeous and deserves several days to a week in order to do it justice. We thought it's natural beauty rivaled the prettiest parts of the South Island of New Zealand - which is saying plenty. There are several spectacular National Parks there that make for pleasant rambles thru the bush or more serious hiking if that's your thing.
A previous suggestion to visit Rottnest Island while in Perth is a good one. It's one of my wife's favorite places in Australia.
For a pleasant stop along the road from Melbourne to Adelaide consider the Tower Hill Animal Reserve near Koroit - just beyond Warnambool. It's another one of our favorite places, with lots of Kangaroos, Emus and Koalas free roaming throughout the area. It's worth half a day by itself. A nice overnight suggestion would be the village of Port Fairy not far away.

We did visit The Tower Hill Animal Reserve and overnighted in Warnambool. We'll look into Rottnest Island. A drive from Melbourne to Adelaide looks interesting. Our family that lives in Melbourne has visited Tasmania. We'll need to get more information from them. Our last big trip to Singapore, Australia and New Zealand was six weeks.

Our end of February 2020 cruise around NZ and ending in Sydney was the first and only cruise we’d been on. It left us wanting to see more of Australia efficiently so that’s why we are considering a 3/4 or whole circumnavigation cruise on HAL in our future. We spent a week in Blenheim NZ before the 2020 cruise and a week in Melbourne AU following the cruise. Things were closing down around us from Covid and we were fortunate to fly home before our state shut down 3 weeks later. We were surprised that we liked the cruise for this type of a winter/summer trip that didn’t require us to drive.

Australia is a huge country and a flight from Sydney to Perth takes 5 hours. About like flying from the east coast of the USA to the west coast.

Thankz Ongonos. I'll send a private message.