Viking Ocean Cruises

(2:45 p.m. EDT) -- Viking Cruises has always positioned itself as an adult experience, but now the company has made it official by no longer accepting guests under the age of 18 on new bookings for its river cruise itineraries.

Viking altered its terms-and-conditions page on its website to reflect the change, which now states that all Viking river cruises booked after August 1 will be open to adults only. The line's previous minimum age for its river cruise itineraries was 12.

"Due to the nature of our cruise and travel itineraries, the Carrier does not maintain facilities or services on our Ships for individuals under the age of 18 years," reads the statement on Viking's website. "For all cruise/cruise tours booked after August 1, 2018 (regardless of departure year), you must be 18 years old on or before the day you are scheduled to embark on the cruise tour. Cruises through 2019 may still have passengers under 18 [if] the cruises were booked prior to August 1, 2018."

Viking has prided itself on the adult nature of its river and ocean itineraries and makes no qualms about the fact that it does not maintain children's facilities or other kid-friendly amenities onboard. Viking's ocean cruises, which debuted in 2015, already limit sailings to passengers 18 and older.

Indeed, Viking chairman Torstein Hagen has affirmed on several occasions that one of the differentiating factors that sets the company apart is its adherence to a quiet, relaxing and educationally stimulating cruise experience designed expressly with adults in mind.

"We're proud of what we are not," Hagen said in June at the launch of the company's fifth oceangoing cruise ship, Viking Orion.  "No children under 18, no umbrella drinks, no photographers and so forth. By peeling off all these things, we make it a much more quiet experience."

Viking is not alone in offering cruises that cater to adults. UK-based P&O has designated certain vessels in its fleet as adults-only, while U by Uniworld also maintains an adults-only policy for its river cruises, stating that passengers must be 18 years of age or older at the time the sailing begins.

-- By Aaron Saunders, Cruise Critic Contributor