Peeling film or whatever it is(tint??)— see picture

That’s a fault with the adhesion of the clear coat. Googling this will provide lots of links explaining the cause and how to rectify it.

I’d recommend you check what the applicable warranty is in your country, it may still be covered.

 

And even if the first dealer tells you it is not covered......check with Toyota directly.
It should NOT be doing this at only 2 years old.

If.....the car was repainted after it left the factory, then forget the warranty and see a body shop.

 

Doesn't look like a painted area...

 

It's some sort of a clear-coat. It should not do that, but AZ is tough on paint, as you probably already know. I'd try the dealer and the warranty, but you're probably close to the expiration.

 

That panel is plastic I think, meaning it has a different paint regime from the steel/aluminium panels. I've had that in a previous car on a plastic fill piece - my 2016 PRIUS is fine. But mine is parked undercover almost all the time.

Is yours parked regularly in the sun?

As mentioned, try warrantly.

Otherwise, a spray painter could re-finish it if it's out of warranty.

 

Same happened to the spoiler on my 2010. These items are finished prior to installation. You can "re-finish" them, but they will show every flaw if not prep'ed right. With a little "yes Sir, no Mam, thank you, please" you might get some "good faith" help from your Dealership...if they have their own body shop...but don't count on it.

 

I could be wrong, but I suspect that it's painted in the factory - mine has the appearance of a painted surface, maybe black with a clear tint - but I think it's plastic underneath?

 

Is that a "snap-on" panel? If so I bet you could find replacements. Consult the parts counter at your dealer for a part number.

 

That's pretty pathetic for a 2~3 year old car.

 

call toyota customer service. ask if you can email them pics. ask for 'goodwill warranty help', it's always worth a shot

 

Is it item 1 here:

Exterior Trim - Quarter Panel for 2016 Toyota Prius | McGeorge Toyota Parts

$85 plus shipping.

If it's relatively easy to pop them off, maybe DIY, using a can of spray paint, or Plasti-Dip?

Searching for the part number (62506-47011), here's a pic giving a bit of a clue about the fasteners:

Side Moulding for 2016 - 2018 Toyota PRIUS ZVW52 | Japan sales region, , 17757828-912573

 

Looking at those fasteners, I'm guessing that you'll break the existing ones taking it off. But then with new fasteners you just push it and snap it back on again.