Bells of the Catholic churches in Zagreb Archdiocese tolled for 15 minutes.
In the central Adriatic city of Split, ships also sounded their sirens in tribute to the pope.
In the eastern Croatian town of Dalj, bells of both the local Catholic and Serb Orthodox church tolled in mourning.
Many schools and colleges did not hold classes on Friday morning so as to make it possible for teachers and students to watch the TV coverage of the funeral.
The coffin with the remains of Pope Karol Wojtyla will be buried in the grave above which there is a sculpture of the Virgin Mary, made by Croatian sculptor Ivan Duknovic in the 15th century.
Services in commemoration of the Polish pontiff will be held in all Croatian towns and cities on Friday
Apostolic Nuncio to Croatia Francesco-Javier Lozano will say Mass in the Zagreb cathedral at 18:00 hrs Friday.
Many Croatian towns and municipalities have in recent days been naming their streets, squares or some other public buildings and facilities after Pope Karol Wojtyla.