The line’s Summer at Sea voyages will take place onboard Queen Elizabeth from July to October and feature scenic cruises along the UK coastline between three and 12 nights.
Sailings will be exclusive to UK residents who have received two doses of a Covid-19 vaccine.
Cunard said its record-breaking day followed “a phenomenal response” to its Centenary World Voyages onboard Queen Mary 2 and Queen Victoria in 2023, which recently went on sale.
Cunard president Simon Palethorpe said the line’s bookings boost showed customers’ "desire to travel with Cunard is stronger than ever".
"In perhaps an indication that guests are upgrading having not travelled for a while, suites onboard these voyages pretty well sold-out at the end of the first day of sales, with only one top suite remaining," he said.
"We are delighted by this response from guests and particular thanks to all of our agent partners for their continued work supporting guest bookings. We’re really looking forward to welcoming guests back onboard this summer."
