who tried to find the fountain of youth and had boars

Juan Ponce de León is the person most commonly linked to the Fountain of Youth, and the “boars” detail sounds like a mix-up with his Florida expedition story.

Who it was

Ponce de León was the 16th-century Spanish explorer tied to the legend of searching for the Fountain of Youth in Florida. Some later accounts and retellings turned that into a more dramatic myth, even though historians note there’s no solid evidence he was actually hunting the fountain.

About the boars

The “boars” part does not match the standard Fountain of Youth story in the sources I found. It may be a confusion with another tale, or with a different explorer/adventure story that involved wild animals.

Quick answer

So the likely answer is Juan Ponce de León.