Sometimes the cruise lines do some deals with single travellers. watch out for some extra discounts that are on royal caribbean just now. there is another way that this can be done for you , get your agent to price flight only most ships with rci sail from miami so you can possibly pick up a virgin flt reasonably , stay as long as you want before the cruise , the agent will then price a "cruise only" for you , these prices are fab , as rci tends to charge quite a lot for flights . this way you can save money too! hope you get a fab deal i do all my cruise holidays this way .. michel.
Not sure about Royal carribbean but know that when I've cruised alone the supplement varies depending on the cabin class - the suites and outside with balcony are usually 100% supplement, others are less but there is no doubt it is far more expensive cruising or having any other holiday on your own. Don't let that put you off - shop around - and try ang get the best deal. i find cruisng far and away the best type of holiday to do on your own.
There is no set amount for a single traveller - work on around a 50 - 75% increase.
Monarch Classic Cruises are offering 3/4 & 7 night cruises from Athens with no single supplement for September & the first two weeks in October. 7 nt price from £599.
Marco Polo (Orient Lines)sometimes has late bargains with no Single supplement. Check out their website for late offers, or find a good cruise travel agent & get them to advise you when offers come in. Otherwise, I usually book very early & get much bigger discounts. QE11 & Fred Olsen ships have single cabins, & Voyage of Discovery are worth a try. Good Luck.