The adults-only vessel will sail the Rhine, Main and Moselle rivers, as well as Dutch and Belgian waterways, next summer and will be equipped 96 cabins.
During the day, the line’s new multi-use venue, Reflections, will host the fleet’s first onboard pool with panoramic views and a retractable roof for year-round use. In the evening, the pool floor will rise to create a dining space for up to 36 guests.
It will offer an a la carte menu featuring Italian-inspired dishes such as arancini, caprese salads, charcuterie and pasta dishes. Tui will also use the venue to host live music and film screenings.
Elsewhere, there will be barbecues and ice cream parties on the top deck.
The Observatory is described by Tui River Cruises as "the heartbeat of the ship" and is another new venue. It will host nightly entertainment from the line’s entertainment team who will put on vocal productions, music, quizzes, film showings and silent discos.
Furthermore, the space will also host afternoon tea which includes tasty sandwiches, cakes, scones and a selection of teas.
Tui Aria will be a Full Board Plus ship which means guests can get tea, coffee, soft drinks, wine and beer with meals. Any other drinks need to be paid for, or passengers can upgrade to all-inclusive, the line explained.
Katy Berzins, head of river cruises at Tui River Cruises, said: "Tui Aria marks a bold new chapter for Tui River Cruises, reflecting our commitment to innovation and guest experience. Aria has been designed to offer more flexibility for our customers – whether they’re seasoned river cruisers or new to river cruise."
She added: "Reflections, our new multi-use innovative venue, transforms from a poolside area by day to a stylish dining venue by night, offering more choice for our customers.
"Alongside new itineraries, additional regional flight options, and thoughtfully designed onboard experiences, Tui Aria opens up even more ways for customers to explore Europe’s rivers in style.”