We booked a February 2024 cruise back in May, 2023. Our PIF was July 2023. As others have noted, Viking does have a much earlier PIF date than other cruise lines. I’m not sure I believe all the comments about cruises filling up 1-2 years in advance as it seems there is still a few cabins available for my sailing next month, but I think it’s highly variable and dependent on the itinerary.
It’s not discrimination against solo cruisers as a 100% single supplement is pretty much industry standard. For future cruises, you can always take a chance and book much closer to the sailing date so you don’t have the $$$ outlay so far in advance of the sailing date, however, you will be limited on cabin selection and likely pay a higher price than those that booked further out.
This is our 2nd cruise on Viking and we love the onboard product, but we’ll see if we take a 3rd cruise with them. Hope you enjoy your cruise.