A message on the brand’s website now instructs customers to search for "Thomas Cook hotels". Bookings are no longer being taken.
The decision to close the B2C website comes only two years after it underwent a rebrand and launched its first ever television advertising campaign.
The adverts, which featured a couple and the tagline “anything for you cupcake”, were slammed by residents of Birmingham for the use of an exaggerated accent.
A Thomas Cook spokesperson said: “The marketing strategy for Thomas Cook has changed significantly over the last year, with an increased focus on the Thomas Cook master brand, particularly in the consumer-facing, hotel-only space.
"We are now offering all hotels previously offered by Hotels4U on thomascook.com, which enables us to ensure that our product offering is all available in one place to build a one stop shop for all our customers’ travel needs.”
The holiday giant bought Hotels4U for £21.8 million in 2008. It underwent a rebrand in late 2013 before launching an advertising campaign in early 2014.
Hotels4U was expected to go to court in late 2014 to battle HMRC in the wake of the Medhotels case but it was cancelled at the last minute.
Thomas Cook’s trade-facing bed bank Medhotels is unaffected by the change.