Birthday celebrants have until the end of the year on Dec. 31 to register and take advantage of the offer.
President and CEO Greg Bombard said the program made visitors' special day on the island even more meaningful as other visitors, residents and business owners wished them a happy day.
"Catalina Express wishes to thank its more than 45 island partners who participated in the Birthday Island program over the past six years, offering discounts, perks and value-added products and services for birthday celebrants," Bombard said.
The promotion started on the company's 30th anniversary in 2012, resulting in nearly 500,000 registrations and 200,000 round-trip voyages.
Visit the Catalina Express website to sign up for a birthday ride before the year ends.