Travellers can also benefit from free changes on existing and newly booked cruises due to sail between 2 August and 25 October, affordable testing and vaccinated-only customers onboard.
Tui said it was also working with test provider Chronomics to create "affordable, cruise specific" testing packages.
Chris Hackney, Tui River Cruises’ managing director, said: "We are so confident people will love sailing with us, if for any reason we do not fulfil our promise to deliver a fantastic holiday, and a customer is genuinely not satisfied, we’ll give them their money back.
"Our ships are looking fantastic and are ready and waiting to whisk our customers away to some of Europe’s big-name cities and hidden gems."
