Head to the Malecón in the morning to view an offshore parade of all the Navy ships in port, followed by tour boats and fishing boats flying their nautical flags. The Navy ships lead and the other boats follow and form a circle for a short ceremony honoring Naval personnel.
If you want a treat outside of the normal Vallarta holiday experience, head down to Yelapa for Navy Day where they have a more “traditional” village party. People gather in small pangas (or in whatever boats are in the harbor at the time and everyone (kids, civic leaders, anyone on the beach…) and head out to sea, tossing flowers into the water in a small ceremony and then race back to the beach where a large, rather jovial party takes place all day and well into the night.