Flag of Y Wladfa, a colony established by Welsh immigrants in Argentinian Patagonia in 1865. Today there are 50 000 Welsh descendants in Argentina, of which 5 000 to 12 500 speak Welsh.

Flag in the wild:

The flag takes the blue-white stripes from the Argentinian flag, and the red dragon is a Welsh symbol, although they both take non-standard forms. I'm not able to confirm it, but this may be due to the flag predating the standardization of the Welsh flag. A version using standard elements also seems to exist:

Wikipedia page about Y Wladfa