Why? A seaplane is more environmentally friendly, faster and cheaper.

Faster ?
Shanghai Maglev 431kph / 232 kts
Shinkansen 359 kph / 194 kts
TGV 320 kph / 173 kts plus.
Twin Otter cruise speed at 10,000 ft 182kts , probably slower on floats.
Personally when in Europe ( and if I ever get back there ) I don’t bother with aircraft.
Trains are way easier.

Can't imagine you would want to give up the ability to land at nearby airports... that adds so much flexibility (and risk reduction). Not to mention much better maintenance and storage conditions on land.

Heard a news report the proving flight landing is to happen at 11:00AM today (Tuesday, 15 December).

Its now 13:10, what, if anything, happened?

VH-IOV It came, it saw, it went.

Door to door it would be faster on the Twin Otter. A High Speed train isn't going to pull out of Central and start doing 300KM/H. Additional to that Trains don't go in a straight line so it would have further to travel.

From the Canberra Times
Sydney Seaplanes demonstration flight from Rose Bay to Lake Burley Griffin to test for future route | The Canberra Times | Canberra, ACT

Article said 1st take-off of the day would be from Canberra Airport (in winter at least).

Comments from National Capital Authority and similar seem to be fairly positive e.g. "...we don't have a fundamental problem with it. It could potentially be very good for tourism and activation of the lake."

Just wondering if the prevailing north-westerly winds would mean an approach over the Chinese Embassy ...

Nice but when I'm in the Maldives I take a Twin Otter on floats - much more comfortable and quicker than the boats...

I doubt CASA would approve a Caravan on floats to do RPT in between Sydney and Canberra. I also doubt the aircraft would be approved for ASEPTA with floats on. How can the aircraft achieve the engine failure after take off turn back requirements with floats under it? I could understand them approving RPT up the coast to Newcastle if all the flying was done over water, however anything over land and particularly in between Sydney and Canberra doesn’t make sense. Winter would be interesting with freezing levels below lowest safes in an aircraft without boots, thought we stopped doing that kind of RPT stuff about 15 years ago.

I also doubt it was a proving flight with CASA onboard approving the operation to use a Twin Otter. A proving flight is normally done with the introduction of a new type and/or a new RPT route. Has the company actually got a Twin Otter on floats in Australia?

Here’s the beast!

https://dornierseawings.com/products/seastar/

Multi IFR and fast. Not cheap to buy but operationally looks great.

A quick scan of the register turns up zero Twotters with VH- regos so I'm guessing no.

Just had a quick look at the Dornier website .
85% Chinese owned now !
It’s like a viral video clip , everyday there’s a new one of someone selling out to the chinese.

The Dornier lineage all the way back 100 years to the Do J "Whale" is pretty striking.

Well it would be pretty fare to assume that this thread is fake news without a Twin Otter on the Australian register to be seen!

I though there was still a 200 series Twin Otter (ex P2-ALS) still being operated out of the Gold Coast, has that been exported? Not sure what the Australian registration was.

There are 2 on the register. Running around the Brisbane area to Lady Elliot Island.

On the basis that I've looked straight past my keys when I've been looking for them it would be fair to say that it's not beyond the realm of possibilities I missed them.

On second look it turns out that unlike virtually every other DHC model on the register where there's either a space or hyphen separating DHC from the model number, the Twotters are under 'DHC6' (and that's despite there being DHC-6 Series 200 and DHC-6-300 on the drop down).

Any old how, so yes, two. BVS and ZKF.

Don’t sweat it Mick, the CASA rego website is not that intuitive! Indeed, DHC-6 comes up with zero! Go figure!

Ta. I've never been keen to blame my tools for poor work. Searches using "DHC-6 Series 200" and "DHC-6-300", which actually appear in the drop down for Model, also turn up zero. A salutary lesson learned.

Full marks to Sydney Seaplanes for commiting more aviation. It's laughable to read the comments from the peanut gallery - but it is the silly season.