When are Star Wars Days?

Have read several times about Star Wars Day. Is it only Cruises on May the 4th? Or is it a dress up type day on many sailings?

There are a series of cruises advertised as "Star Wars Day at Sea." It is not just May 4. You can see the scheduled dates on the DCL web site. It is about 6 or 8 cruises per year. There are also Marvel Day at Sea cruises. There is a lot more to it than just "dress up."