What religion is Indiana Jones

Maybe he is an athiest

Most likely some British Isle based Protestant Christian denomination such as Presbyterian as mentioned here earlier. He most likely observed certain traditions but was not a weekly church goer which most likely separated him from his father who no doubt was devout whenever he got the chance. Indy was a believer in the sense of the contemporary era that the film franchise existed in. He believed in God and Christ but believed he had no time for church and considered some believers as flawed or fallible.

Cult of Spider-Man.

He in fact gave the impression of being a Christian in the latest movie. He had a big cross in his home.

I can't believe that Jones has any actual religious faith. Because of when and where he grew up, he was probably dragged to church on a regular basis, and may vaguely identify as a Christian, and if someone makes an effort to pull the adult Indy into a Christmas service he'd probably go without too much protest.

But Faith-with-a-capital-F??? No way!

No, he probably views religious texts as a good source of information about ancient treasures, no more.

He lived in Utah and was a a Boy Scout.

Just sayin...

Bellocq already told him: "Archeology is our religion ".