Carnival Cruise Line is waiving non-commissionable fees for third and fourth passengers booked in the same cabin.

The promotion runs until May 31 and is available on selected cruises this autumn.

Discounted rates are being offered to consumers as part of the initiative in a bid to attract more families and friends.

The offer is the latest addition to #thelist of Carnival’s travel agent incentive which includes a new website, dedicated Facebook page, fam trips, prizes and commissions on future cruise credits.

Sales and trade marketing senior vice president Adolfo Perez said: “As we grow #thelist we’re looking to activate initiatives that benefit both consumers and our travel partners.

“This is a fantastic opportunity for agents to get their clients great rates on Carnival’s autumn cruises and earn higher commission, making it a win-win for everyone.”

The 26-ship US line has three new ships due for delivery – the 133,500-ton Carnival Panorama in 2019 and two as-yet-unnamed 180,000-ton ships in 2020 and 2022.