Catalina Island vs Santa Catalina Island

Catalina Island and Santa Catalina Island both are nouns.

Word	Noun	Adjective	Verb	Adverb
Catalina Island	Yes	No	No	No
Santa Catalina Island	Yes	No	No	No

As nouns, Catalina Island and Santa Catalina Island are synonyms defined as:

Catalina Island and Santa Catalina Island: an island resort in the Pacific off the southwestern coast of California

Other synonyms of Catalina Island include Santa Catalina.

Catalina Island (noun)	Santa Catalina Island (noun)
an island resort in the Pacific off the southwestern coast of California	an island resort in the Pacific off the southwestern coast of California