Neptunus is a professional baseball and softball club in Rotterdam, the Netherlands.

[citation needed] Neptunus is the most successful team in the Honkbal Hoofdklasse, the top level of professional baseball in the Netherlands.

During that dominant stretch, Neptunus also won the continental European Cup five consecutive times from 2000 to 2004.

In 2010, the team set a single-season Dutch league record by winning 39 games.

Although the club fielded a football team in the past, Neptunus is primarily known for baseball and softball.