I have used the H2O waterproof holder for my GT31,s for years there the only comfortable holder that doesn't dig into your Bicep and have lasted ages but cannot seem to find them anymore. I think I purchased on Amazon initially but soo long ago.
Any ideas where you can purchase or worst case an alternative?

I've always used paqua midis but they seem hard to get now. They were for smaller old phones, but phones have grown.

H2Oaudio was bought out, and the phone arm bag is renamed Amphibx. I cant find the original design now but they have a similar but larger design :

h2oaudio.com/products/amphibx-waterproof-smartphone-case

Edit:

I found a website listing the original design:
www.g2a.com/en-au/x-1-powered-by-h2o-audio-amphibx-fit-waterproof-armband-for-smartphones-black-i10000188678001

But you would have to use a USA freight forwarding service as they say they dont ship to Australia.

Here is another in the UK: They may ship to Australia but I cant find the info

order.komaks.com/x-1-h2o-audio-xb1-bk-x.html

Ebay US seller for the original smaller one that suits up to 4" Phones.

www.ebay.com.au/itm/254934961799?hash=item3b5b4ece87:g:CCEAAOSw-vpfDxwV

Thanks I have tried so far no success

Try Aquapac.

aquapac.net

Take a look here www.fidlock-bike.com/en/produkt/armband/

Select to expand quote

decrepit said..
I've always used paqua midis but they seem hard to get now. They were for smaller old phones, but phones have grown.

Fully agree, the Paquas are great! I use it for the gyro1, very compact such it fits also the car key in there. Since it is keyless entry I can easily lock/unlock the car without removing it.

www.whitworths.com.au/aquapac-armband-small-phone-case

Would this work Byron?

kayakshopaustralia.com.au/aquapac-217-waterproof-gps-armband-case-medium/

Select to expand quote

Tony Polony said..
www.whitworths.com.au/aquapac-armband-small-phone-case

Would this work Byron?

I think my last phone fitted in that but it was tight. I now have a Galaxy A32 and it's bigger . If you have a larger modern phone I think it will be too small.

My Paqua packed up this week after many good years - tried to get a replacement but they're not available any more it seems. So I got an Aquapac instead...seems good so far...actually easier and a bit more comfortable than the Pacqua...oh and I use a GT31...

Paqua Midi is for sale on Ebay

www.ebay.com.au/itm/303573739150

Has that gone up in price? I seem to remember a figure beginning with 4 not 6

Select to expand quote

decrepit said..
Has that gone up in price? I seem to remember a figure beginning with 4 not 6

I bought my last one for under $50 a few years ago

Surfsailaustralia.com.au also sell them but are currently out of stock.

I use a food sealer to bag the gt-31, then you can put it in your favorite holder without worrying if it leaks. Make the food bag longer and you can re-seal it many times

I tend to make my own cases out of Perspex

I bought the aqua small and it doesn't fit so will return.
the medium might be ok but they don't sell it.