...is there anyway I can tell for sure?
If it gets a pink blush on the ventral surface but does not develop scarlet colour on the chest than it is definitely not a male.
The reason for my previous post was to encourage you to make the comparisons and see for yourself. That’s the best way to learn. Based on the photos provided, it is 95%+ a female. Individuals, both male and female, do vary in their colour and form, but within limits, and working from photos for certain things is just not the same as being able to hold the animal and inspect it.
I do have a query about the origin of these two individuals. In both females it is difficult to clearly see/confirm the eye to ear dark stripe, which should be clearly visible in sub-adults attaining breeding age. The other thing is the colour and pattern on the throat. You get this in many northern NSW/Qld specimens but it is also present in Gippsland female.
I was under the impression ALL dragons can be sexed by the hemipenal bulges in the tail . Although I know male eastern water dragons have a red throat.
In general the existence of hemipenal bulges is the case for most adult male dragons. However, in a few species it is far less obvious and water dragons are one of those. The base of the tail (I,e, adjacent to the vent) is thicker in males because of the presence of the hemipenes. Unfortunately there is a finger across that area in the photo of the ventral surface provided.
I think you are referring to the chest and upper arms, rather than the “throat”, which develop a scarlet colour in males. Sometimes you can get a bit of red showing on the back of the gular fold. The more northerly individuals often develop a yellowish throat colour, usually with darker streaks. The amount of the belly that colours up is variable.
