Brittany Ferries claims to have eliminated nearly 5.7 million plastic items across its fleet.
Environmentally-friendly alternatives, such as bamboo, cardboard, paper and wood, have replaced single-use plastic items in the last 18 months.
Disposable shower gel sachets have been replaced with dispensers filled with eco-friendly gels and plastic bags in dustbins have been removed.
The firm will launch its first LNG-powered ship, Honfleur, in 2020, plus two more vessels in 2021 and 2022.
Chief executive Christophe Mathieu said: “The sea is our home, so of course we’re deeply aware not only of its beauty, but also its fragility.
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“By tackling single-use plastics, we are determined to take responsibility and make a significant contribution to collective efforts to protect the seas upon which we sail.
“We couldn’t have done this alone: we’re working closely with our suppliers to raise standards and to find innovative and creative solutions.
“We’re also working with our customers and colleagues, who are increasingly driving our efforts to make changes. We want to make it easier for them to consume and recycle in line with their and our values whilst they’re on board our ships.
“For sure, there’s much more to do, but this is a positive step forward, part of our long term mission to incorporate sustainability into everything that we do.”
It comes after Claire Artagnan joined the company earlier this year as its first ‘eco-responsibility’ manager.