across the UK, France, Germany, Belgium, Poland and the Netherlands.
SeaFrance hope the revamped site will increase online revenue by providing an improved user experience, with an updated look and feel.
The site will be fully content managed and feature a redesigned and simplified booking process to aid conversion and assist cross-sell and up-sell.
The design will focus on building excitement around the run up to the journey, bringing to life the onboard brand experience and then provide destination information to inspire people to book.
The win is Steel's first appointment by the ferry firm SeaFrance although it has been the sole retained agency for its subsidiary SeaFrance Ltd for the past 13 years, handling all digital and below-the-line communication.
Les Hughes, managing partner at Steel, said: "We are very excited about working on our first international project for SeaFrance.
"We've been working very closely with SeaFrance UK to improve customer acquisition and conversion on every level and our involvement in the website redesign will ensure the whole sales process is fully connected."
Kathy Fleta, commercial director of SeaFrance Group, said: "Digital marketing is evolving rapidly and our commercial site, seafrance.com, must keep pace at this time of unprecedented competition.
"The site redesign will ensure we can respond more effectively to the habits of internet users in general and specifically to the expectations of our loyal customers.
"Seafrance.com is at the heart of our forward thinking approach and we are confident of Steel's ability to successfully achieve our sales objectives using their flair for artistic design."