My SIL is a frequent cruiser, 2-3 times a year (never on DCL yet) and has a cruise companion, but due to age and health that may be coming to an end. I think in the future, she may be interested in cruising with us. I have said I would only agree to this if she had her own separate cabin. I just took a look at the current rates for our upcoming cruise. Adult fare in our 8C category is 2100. That would mean she would have to pay 4200 to get a cabin on her own, based on double occupancy. (actually more, because she usually only cruises with a balcony) We also cruise with our dd (under 18) and her fare right now for child/3rd person is 1600. If the time ever comes that SIL wants to cruise with us, I would propose the following to her: She shares a cabin with our dd (her niece) and although she has to pay for two full fares (still 4200 in this example), we would refund her the 1600 which is the portion we would pay for our dd anyway. My husband says she won't understand this and will think that we should pay 2100 for our dd to share 1/2 the cabin, as the 2nd passenger. But the point is, we don't mind sharing with our dd at all, so why would we pay more? My option at least allows her to recoup 1600 of her double occupancy fare, leaving her paying 2100 for herself and 500 for our dd, but at least she's not paying 4200 double occupancy on her own. Or she can totally cruise alone in her own cabin and pay 4200. And I would still only be willing to pay whatever our cabin fare was going to be for our dd, no matter what type of cabin my SIL wanted, ie: balcony. Anyone else run into issues when trying to cruise with an extra "single"? Of course, I wouldn't even suggest putting my dd with her if SIL brought along some other friend to share her cabin/costs.