Is there an AirPrint or other app solution that is compatible with an HP Photosmart C309a wireless printer? The HP Smart app doesn't appear to work and the Apple Airprint app does not list the HP c309a (or any c309 model) as a supported device.

Try this had some success with it previously through it does require an intermediary Mac as a print server.

https://www.decisivetactics.com/products/printopia/

Your HP C309a is not an AirPrint compatible printer. You have already learned this. There may be other solutions available out there to print with HP C309a wirelessly and the best place to look for those solutions is the ➔ HP Printer Support page.

Axel F.

From this page:

https://support.hp.com/us-en/document/ish_2843711-2427128-16

You appear to be out of luck.

My guess is this printer is too old to be supported by either AirPrint or HP’s methods.

I found a twelve year old product review, so the printer is at least that old.