How do cabins on river cruise ships compare to those on ocean ships? Will I have as much choice in cabins on a river ship as I do on an ocean ship?

Cabins on river cruise ships can vary widely from line to line. One thing that is different from their ocean counterparts is that you won't find inside cabins on river cruises; all staterooms have at least a window.

Cabins on river vessels tend to be slightly smaller than their ocean counterparts because the ships themselves are much smaller. They have to be that way because in Europe, the vessels must be able to fit through narrow locks and canals, and travel under bridges.

Standard river cruise cabins in Europe run between 150 and 170 square feet, with suites around 220 square feet. Some cruise lines also have single cabins, which measure around 130 square feet. Ironically, in Asia, where river cruise ships are very small with 50 passengers or less, the cabins are often larger at 220 square feet.

In general, you'll find fewer categories of cabins on river ships. Most lines in Europe only have four classes: window only or "river view," French balcony, balcony and suites, although there are some variations.

On Cruise Critic's message boards, I see people talking about "aquarium class." What is that?

Aquarium class is a humorous term for the lower deck cabins that fall below the waterline. These cabins have a window, often high on the wall, that lets in light. But you shouldn't expect to have a view from it unless you stand on a chair. You also cannot open these windows. (If you did, you'd find yourself pretty wet!)

One exception to this is found on Tauck's newer ships: Inspire, Savor, Grace and Joy. These ships have Loft staterooms that essentially put the seating area of the lower deck cabins on a walk-up landing area in front of the window. The windows in these rooms are also positioned high enough that they can be opened to let in fresh air.

What's a French balcony?

Viking, Avalon, Uniworld, AmaWaterways, Tauck, Crystal, CroisiEurope and Vantage all offer rooms with French balconies, which are sliding doors that open to let in air. You can't walk out on these balconies, although sometimes the cruise lines put tables and chairs in front of them so you can feel like you're outside. There's also a railing so you won't plunge into the water.

What other kinds of balconies do river cruise ships have?

In many of its cabins, Avalon has an expanded variation on French balconies called "open air balconies." This means that the door slides the entire length of the room; again, you can't step outside though.

Emerald Waterways and Scenic have something similar on their ships, which they call "panorama balconies"; instead of sliding open like a door, the windows lower with a push of a button.

I want a "real" walkout veranda. Which river cruise lines have those?

On its newest ships, AmaWaterways has "twin balcony" staterooms, which combine a French balcony off the living area and an outdoor balcony where you can step out off the bedroom.

On its Longships, Viking has a wide selection of balcony staterooms where there's room for a table and chair. Grand Circle also has some "step out" balconies on its ships.

Keep in mind that a real balcony isn't as always desirable on a river cruise ship as it is on an ocean ship. For one thing, the balconies cut into the room's square footage, so you are sacrificing precious space to sit outdoors. Also, the weather in Europe can be very changeable, particularly in the shoulder seasons. For a Christmas cruise, you aren't going to want a balcony at all; it's simply too cold!

Do any river cruise ships have suites?

Yes, although as in ocean cruising, you'll want to study the cabin configurations carefully to make sure you're getting a true two-room suite; many staterooms booked as suites are simply larger and don't have separate bedrooms and living rooms.

On Avalon "Suite Ships," all cabins are called suites. But even its 300-square-foot Royal Suite doesn't have a separate living area. Ditto suites on AmaWaterways and Tauck.

On Scenic, bedrooms in the 360-square-foot Royal Balcony Suite and the 475-square-foot Royal One Bedroom Suite are separated from the living area. Because all of the cabins on Scenic ships have glass-enclosed lounge areas that can open up as balconies, they do have the separation between living area and sleeping area that you expect from a suite (as does sister line Emerald). On Emerald's "Star-Ships," the bedroom is separated from the living room with a sliding door in the one-bedroom Owners Suite. Vantage has a true Owners Suite as well (at 330 square feet).

Uniworld's "Super Ships" each have a 401-square-foot Royal Suite with a separate living area; the suites themselves are only one room (although they're fairly spacious at 305 square feet). The line's other ships do not have separate living and sleeping areas in any cabins.

On Viking's Longships, you'll find the Explorer Suite, which -- at 445 square feet -- is one of the largest on European river ships. These staterooms do have the bedroom walled off from the living area.

And finally, Crystal River Cruises is entering the picture in 2016 with a two-bedroom suite that measures a whopping 860 square feet. The cabin has two separate bedrooms, in addition to a separate living area and dining room.

What amenities do standard river cruise cabins have?

Much like those on an ocean cruise ship, river cruise cabins have a queen-size bed that can be turned into two twins, nightstands and bedside lights, closets and drawers for your things, a vanity or mirror in the room and either a sofa and table, or two chairs and a table. Suitcases can be stored under the bed. Flat-screen TVs, either with or without movies on demand, are usually available for entertainment. Most river cruise lines have included Wi-Fi in their fares, although the quality of the signal can vary in the cabins.

Older river ships, such as those used by Grand Circle, do have immovable twin beds. You'll want to check the cabin configuration before you book.

On some lines, you'll also find a mini-fridge and on most -- but not all -- bottled water is complimentary.

Are all the layouts of river cruise cabins standard?

On most river cruise ships, the layout will be familiar to anyone who has been in a hotel room or cruise ship before. The door to the bathroom will likely be in the hallway, as soon as you enter the room; the closets will be facing the beds, which will be parallel to the outside wall, and the table and chairs (or sofa) will be near the window, French balcony or balcony. On some ships, the bathroom may be across from the bed.

Notably, some river cruise lines have tinkered with this setup. Avalon Waterways has designed its cabins so the beds face the windows, particularly nice for scenic cruising. Tauck has a similar setup on some of its ships, particularly with its Loft cabins (mentioned earlier).

Do river cruise lines have accessible cabins?

Unfortunately, there's no blanket answer to this question. River cruising overall isn't necessarily the most friendly to passengers with limited mobility and some of the biggest names in river cruising -- Avalon, Viking and Uniworld -- do not have accessible cabins (although the latter does have grips in its bathrooms). While newer river cruise ships do have elevators, these often don't go all the way to the sun deck -- a real drawback when you consider that passengers often have to go up to the top deck and board a neighboring ship to disembark. Another factor is the gangway, which is often too steep and narrow for wheelchairs.

Scenic does have accessible cabins on all of its ships, as does sister company Emerald Waterways and CroisiEurope. Some of AmaWaterways' ships have wider doors and modified bathrooms. The newer ships on Vantage have at least one accessible cabin.

But even if you can find a cabin that works, keep in mind that river cruise excursions often require a lot of walking over cobblestoned streets. Some lines require passengers with mobility issues to bring a companion with them. For more, read A Guide to Accessible River Cruises.

Can river cruise cabins fit more than two people?

It used to be that river cruises were designed primarily for couples in their golden years, with little flexibility for families. That's changed, as lines are realizing that river cruising can be a fun and educational vacation for children and teens.

AmaWaterways is the first river cruise line to actually design a ship with groups and multi-generational travelers in mind. The two family-friendly ships, AmaStella and AmaViola, debuted in 2016. The accommodations include 12 staterooms that can house up to three family members each; six sets of adjoining cabins that can be connected via an internal doorway, accommodating families of up to five; and four suites with convertible sofa beds that can accommodate families of up to four.

On Tauck's newer ships, cabins have full-size sofa beds that can be used by families; up to four people can sleep in one cabin. (The line is also retrofitting its older ships so more cabins will have sofa beds.) Tauck also has suites that can accommodate three adults over 18, as well as two parents and a child. The recommended minimum age for Tauck's family river cruises is eight years old.

Uniworld, which also offers family-oriented cruises, has some cabins with sofa beds on most of its ships. This is one line where the ships can vary widely, so check before you book.

While regular cabins on Vantage's ship, River Venture, do not have room for a third berth, the Owners Suite does have a sofa that converts to a bed.

For more, read Best Family River Cruises.

Do any river cruise ships have single cabins?

Yes. A handful of river cruise lines do cater to solo travelers with single cabins. Look to Vantage and AmaWaterways in Europe, and American Queen Steamboat Company in the United States. While Viking's Longships don't have rooms for solos, some of their older ships do.

A lack of single-person cabins doesn't mean that river cruises eschew solo travelers. Far from it. The camaraderie of river cruising means that passengers are often seated at group tables for meals, which makes it easy to meet people. Vantage and Grand Circle offer a roommate matching program. And it's fairly common to find discounts and specials waiving the single supplement.

What will my room steward do for me? Is there a butler?

Room stewards on river cruises perform many of the same services that their ocean counterparts do: namely, tidying up the room several times a day, doing a turndown service and stocking the cabin with fresh water and other necessities. You generally won't find a lot of towel animals on a river cruise, although we saw some spectacular ones -- including spiders, camels and a scorpion -- on our Uniworld cruise in Egypt.

Two river lines are notable for providing butler service to passengers in some categories. Uniworld offers dedicated butler service to all passengers traveling in suites on its European fleet, with the exception of itineraries in Portugal and Russia.

Scenic offers butler service to passengers in every cabin, with set services according to the cabin category. These range from shoeshine, concierge service and restocking the mini-bar in Standard Suites, to packing and unpacking, arranging in-room cocktail drinks and even running a bath in the top suites.

I hate showers. Is there a bathtub?

Generally, most river cruise cabins are shower only, unless you book a suite. Lines that have tubs in their suites include AmaWaterways, Tauck (on its older ships only; the newer ones go for a rain shower instead), Viking (older ships only) and Uniworld (newest ships only). Scenic is notable for having tubs in categories from Junior Suite and above. Crystal's river ship, Crystal Mozart, will also have a bathtub in its upper suite.

What kind of bathroom products do river cruise lines provide?

Brand names vary by line, but in general, river cruise lines seem to have nicer products -- shampoo, conditioner and body gel -- than their ocean counterparts. L'Occitane is used on Vantage, Avalon, AmaWaterways, Scenic and Uniworld. Tauck uses Molton Brown. Viking has its own line of products and what's more, they come in full sizes instead of trial sizes.

Do I have to bring my own hair dryer?

No. All river cruise lines have a hair dryer in the room.

How can I find out more about cabins on a river cruise?

The What to Expect on a River Cruise series is a resource guide, written by Cruise Critic editors and contributors, where we answer the most common questions about river cruises, including dining, cabins and suites, service and onboard activities.