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Every cruise ship has a second layer that most passengers walk straight past. On some ships there’s a room full of washing machines down your corridor. There’s a code word that means “someone just went over the side”, and a bathroom tap whose water is tested to a CDC rulebook.
None of it is secret, exactly. It’s all written down somewhere: in a cruise line FAQ, a federal sanitation manual, a maritime treaty or the small print of your ticket contract. Hardly anyone reads those. We did.
Here’s the short answer. The seven hidden things on a cruise ship that are most helpful to know are: your muster station is printed on your key card, crew announcements use code words, the cabin tap water is safe to drink, some ships have self-service launderettes, there’s a free adults-only deck, you can pay for a tour of the bridge and engine control room, and the ship’s medical centre will bill you for every visit.
7 Hidden Things on a Cruise Ship: The Short Version
Here’s the whole list, with where each rule is written down. The details follow.
| Hidden thing | Where to find it | Who says so |
|---|---|---|
| 1. Your muster station | On your key card, in the app, behind your cabin door | Royal Caribbean and Norwegian FAQs; SOLAS |
| 2. Code words | The PA system: “Alpha”, “Bravo”, “Oscar” | International Code of Signals; line practice varies |
| 3. Drinkable tap water | Your cabin bathroom | CDC Vessel Sanitation Program standards |
| 4. A launderette | Cabin decks on Carnival, Princess and Disney (not Royal Caribbean or Norwegian) | Royal Caribbean FAQ; The Points Guy; Cruise Fever |
| 5. A free adults-only deck | Royal Caribbean’s Solarium (18+), Carnival’s Serenity (21+) | Royal Caribbean’s 2023 announcement; Cruise Hive |
| 6. A tour of the bridge | Book Carnival’s “Behind the Fun” or Royal Caribbean’s All Access Tour | Each line’s own tour listing |
| 7. A medical centre that bills you | On your deck plan; ask guest services | Your ticket contract; Medicare.gov |
1. Your Muster Station Is Printed on Your Key Card
The card that opens your cabin and pays for your cocktails has one more job. It tells you where to go if something goes badly wrong.
Norwegian is the most specific about it. Its FAQ says your assembly station “can be found on the bottom right-hand side of your Freestyle Card” and on the signage behind your stateroom door. Royal Caribbean says your muster station is listed in the app or on your SeaPass card.
This isn’t optional. Royal Caribbean’s FAQ points out that the muster is an international requirement under SOLAS, the Safety of Life at Sea convention, and must happen for embarking passengers before or after the ship leaves port. Its version has three steps: watch the life jacket video, listen to the emergency horn, then report to your station, where a crew member checks you off.
That horn is worth learning. The general emergency alarm is “at least seven short blasts followed by one long blast”, in the wording of the UK’s muster regulations. The same pattern is set internationally through SOLAS and its Life-Saving Appliances Code, as Wikipedia’s entry on the signal sets out. Hear seven short blasts and one long one and it’s not the dinner bell. Go to the station on your card.
What to do: on day one, find your station letter on the card, then walk there from your cabin once. Learn the route by the stairs as well as the lifts.
2. The Crew Talks in Code Over the PA
You’re at the pool and the speakers crackle: “Alpha, Alpha, Alpha, deck 11, portside, aft.” Everyone around you carries on sunbathing. Should you?
Mostly, yes. According to Royal Caribbean Blog, “Alpha” is a common code for a medical emergency, followed by the location. On Royal Caribbean, “Bravo” signals a fire or other serious emergency, “Oscar” means an active man-overboard situation, “Kilo, Kilo, Kilo” calls all crew to their emergency stations, and “Charlie, Charlie, Charlie” or “Zulu, Zulu, Zulu” signals a security threat or a fight. Disney uses entirely different phrases: “Mr. M.O.B.” for man overboard, “Operation Brightstar” for medical emergencies and “Red Party” for a fire.
That variety is the point. Islands notes that the codes “can vary by cruise line and are not standardized across the industry,” and that the US Coast Guard doesn’t mandate specific words. The codes let the crew move quickly without alarming a shipful of passengers. When a call is meant for guests, it says so.
Some of the words do have an official ancestor. In the International Code of Signals, the flag that ships fly for the letter O means, in full, “Man overboard.” The B flag means “I am taking in or discharging or carrying dangerous goods.” Cruise lines didn’t invent “Oscar”. They borrowed it from the sea’s own alphabet.
What to do: if a code names a location near you, stay out of that area so the response team can get through. That’s Royal Caribbean Blog’s advice too. Don’t film it, don’t go and look, and treat any announcement that sounds like a joke with suspicion: we’ve covered the time six passengers got on MSC Divina’s PA.
3. The Tap Water Is Safe to Drink, and the CDC Checks It
Plenty of first-time cruisers pay for bottled water all week because they assume ship water must be dodgy. It isn’t, and there’s a federal rulebook that says why.
Ships make fresh water from seawater. They either push it through reverse-osmosis membranes or boil it and condense the steam. They also load water in port. Islands quotes a Royal Caribbean captain explaining that the water in your sink, shower and toilet comes from the same tank, and that all of it is drinkable.
Then the CDC’s Vessel Sanitation Program 2025 standards take over. They define potable water as water intended for “drinking, washing, bathing, or showering”, and say it “must conform to requirements of the World Health Organization DRINKING WATER standards.” Here are the rules ships are inspected against:
- Section 5.4.1.2.1: the system “must maintain a free HALOGEN residual of greater than or equal to 0.2 MG/L (ppm) and less than or equal to 5.0 MG/L (ppm) throughout the distribution system.” In plain English, there’s always a little disinfectant in every pipe.
- Section 5.6.1.1.1: “A minimum of four POTABLE WATER samples per month must be collected and analyzed for the presence of E. coli,” taken from the forward, aft, upper and lower decks, with the sample sites changed every month.
Those standards are what VSP inspectors score ships against. If you want to see how individual ships do, our guide to the dirtiest cruise ships according to the CDC walks through the actual inspection reports.
What to do: pack a reusable bottle and fill it from the tap. If the ship ever posts a do-not-drink notice, follow it, but that’s the exception, not the rule.
4. Some Ships Have a Launderette Down the Corridor
This is the one that saves real money on a long cruise, and it depends entirely on which line you book.
Carnival has self-service laundry rooms “on all ships except those in the Excel Class,” according to The Points Guy. That means no washers on Mardi Gras, Carnival Celebration or Carnival Jubilee. Cruise Fever, updated in April 2026, agrees and says the ex-Costa Venezia-class ships don’t have them either. It puts the price at “$3.50 per washer load and another $3.50 for a load in the dryer.”
Princess has launderettes across the fleet, and you buy tokens with your OceanMedallion (The Points Guy). Cruise Fever says they cost about $3 per machine. Disney has them too, according to both outlets.
Royal Caribbean is the big no. Its FAQ is blunt: “For safety concerns self-service laundry facilities are not provided onboard our ships.” It doesn’t put irons in cabins either, “as they constitute a fire hazard.” What it offers instead is a wash-and-fold special: “the fixed amount of $34.99 per bag,” stuffed as full as you can get it. Both The Points Guy and Cruise Fever list Norwegian, Celebrity, Holland America and MSC as lines without self-service laundry.
What to do: on a 10-night-plus sailing with Carnival, Princess or Disney, pack for half the trip and plan one laundry session on a quiet sea-day morning. On Royal Caribbean, wait for the wash-and-fold special and share a bag.
5. There’s a Free Adults-Only Deck (Check the Age Limit)
The main pool on a sea day can feel like a water park at a school reunion. On most big ships there’s a calmer pool deck you don’t pay a cent extra for. You just have to be old enough.
Royal Caribbean’s Solarium is now 18 and over. It used to be 16, but in an email in September 2023 the line said: “we have decided to keep our ‘adults-only’ areas consistent, and update the Solarium age restriction from 16+ to 18+ years old,” as quoted by Royal Caribbean Blog and reported by Cruise Fever. Children can still walk through to reach the Solarium Bistro, but they can’t stay or use the pools.
Carnival’s Serenity Adult-Only Retreat is stricter: 21 and over, as Cruise Hive reports and Cruise Mummy confirms. Cruise Mummy says it’s on every ship in the fleet, with no day pass or fee to get in. Expect hot tubs, padded loungers and a bar. The space is free, but the drinks aren’t.
What to do: if you’re a 19- or 20-year-old on Carnival, the Solarium’s 18-plus rule won’t help you. That’s a Royal Caribbean thing. Families with a 16- or 17-year-old should note the 2023 change, because older guides may still say 16.
6. You Can Pay to See the Bridge, the Galley and the Engine Control Room
Most of the ship is behind doors marked “Crew Only”. For a fee, some of those doors open.
Carnival’s Behind the Fun Ultimate Tour is listed at $95 per person on a Miami sailing. It takes in “the ship’s bridge, engine control room, main galley, staff dining areas, storeroom, laundry, and other spaces.” It runs once per cruise on a sea day and is limited to 16 people. The minimum age is 8, and “cameras, bags, recording devices of any kind or cell phones are not permitted.” You get a cap, a group photo on the bridge and snacks. Cruise Hive reported that Carnival made the tour bookable before the cruise, with each tour “typically for fewer than 20 guests.”
Royal Caribbean’s All Access Tour is available on all ships. It covers the main galley, the provision area, the engine control room, the laundry, the crew corridor known as I-95 and the bridge. The line says “prices vary by ship,” and you can book it through the Cruise Planner or on board. There’s a dress code: no bags, no open-toed shoes, no shorts or skirts, and no video cameras. For a real-world price, Royal Caribbean Blog paid $86.99 per person before a 2022 Mariner of the Seas sailing for a two-hour tour.
What to do: book these as soon as your booking opens them, and check the shoe and clothing rules. Flip-flops aren’t allowed on either tour, and Carnival’s runs on just one sea day per cruise.
7. The Medical Centre Is Real, and It Sends You a Bill
Every big ship has a doctor and a small medical centre. What surprises people is that it’s not part of the fare.
Royal Caribbean’s ticket contract puts it in one sentence: “Guest shall pay for all medical care or other personal services requested or required, whether onboard or ashore, including the cost of any emergency medical care or transportation incurred by Carrier.”
Older American cruisers often assume Medicare will help. It mostly won’t. Medicare’s own fact sheet, Medicare Coverage Outside the United States, says: “Medicare doesn’t cover health care services you get when the ship is more than 6 hours away from a U.S. port.” It may cover care if the doctor is legally allowed to treat you on board and the ship is in a US port or within six hours of one, “regardless of whether it’s an emergency.” Kiplinger explains the same six-hour rule.
What to do: buy travel insurance with medical and evacuation cover, and keep every receipt from the medical centre for your claim. Our guide to whether you need insurance for a cruise compares each big line’s own plan, figure by figure.
Your First-Day Checklist
- Find the muster station on your key card, and walk the route by the stairs.
- Learn the alarm: seven short blasts and one long one means go to your station.
- Fill a reusable bottle from your cabin tap.
- Check whether your ship has a launderette, or when the wash-and-fold special runs.
- Find the adults-only deck if you’re old enough, and check the age limit if you’re travelling with teens.
- Book the behind-the-scenes tour early, in closed-toe shoes.
- Put your travel insurer’s emergency number in your phone before you sail.
Quick Answers
Is tap water safe to drink on a cruise ship?
Yes. Under the CDC’s Vessel Sanitation Program standards, potable water on board must meet World Health Organization drinking water standards, keep a disinfectant residual throughout the pipes, and be tested for E. coli at least four times a month.
Can you do your own laundry on a cruise ship?
On Carnival (except the Excel-class ships), Princess and Disney, yes, in self-service launderettes for a few dollars a load. Royal Caribbean, Norwegian, Celebrity, Holland America and MSC don’t have self-service laundry and offer paid laundry services instead.
What does “Oscar” mean on a cruise ship?
On Royal Caribbean and some other lines, “Oscar” is the crew code for a person overboard. It comes from the International Code of Signals, where the O flag means “Man overboard.” Codes vary by line, so stay clear of the area named and follow plain-language instructions.
How old do you have to be for the Solarium or Serenity?
Royal Caribbean’s Solarium has been 18 and over since a 2023 change (it was 16). Carnival’s Serenity Adult-Only Retreat is 21 and over. Both are free to use.
Can you tour the bridge on a cruise ship?
Yes, on a paid tour. Carnival’s Behind the Fun Ultimate Tour (listed at $95, maximum 16 guests, ages 8 and up) and Royal Caribbean’s All Access Tour (price varies by ship) both include the bridge, the engine control room and the galley.
The Bottom Line
A cruise ship is a floating town, and like any town it has its own rules, signals and services that locals know and visitors miss. Read your key card, learn the alarm, drink the water, find the washing machines, claim a quiet lounger, book the tour and insure yourself for the doctor. Then go back to the pool. You’ve earned it.
Cruise Chaos earns nothing from cruise lines, tour operators or booking links. Every fact in this guide links to where we read it. Policies, prices and age limits were checked on October 3, 2026. If something has changed since, tell us and we’ll correct it.
Coming up on Cruise Chaos: the 5 most forgotten cruise items, and what they cost to replace once you’re on board.
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Keep Reading
- 6 Must-Know Cruise Hacks
- The Dirtiest Cruise Ships According to the CDC
- Do You Need Insurance for a Cruise? What Your Ticket Contract Says You’ll Pay
Sources
- Norwegian Cruise Line: What is a muster station and where can I find mine?
- Royal Caribbean: What is a muster drill?
- UK legislation: The Merchant Shipping (Musters, Training and Decision Support Systems) Regulations 1999, regulation 6
- Wikipedia: General emergency signal and International maritime signal flags (citing the IMO’s International Code of Signals, 2005 edition)
- Royal Caribbean Blog: ‘Alpha’ is a code word cruise employees use
- Islands: 5 code phrases you never want to hear on a cruise ship and Is it actually safe to drink the tap water on your cruise?
- CDC: Vessel Sanitation Program 2025 Environmental Public Health Standards (PDF)
- Royal Caribbean: Onboard laundry services
- The Points Guy: Cruise ship laundry
- Cruise Fever: Cruise ship laundry, the lines with self-service laundry rooms
- Solarium age change: Royal Caribbean Blog and Cruise Fever
- Carnival Serenity: Cruise Hive and Cruise Mummy
- Carnival: Behind The Fun Ultimate Tour; Cruise Hive: Popular Carnival tour to be available for pre-cruise reservations
- Royal Caribbean: What is the All Access Tour?; Royal Caribbean Blog: What the behind-the-scenes tour is like
- Royal Caribbean: Cruise/CruiseTour Ticket Contract (US)
- Medicare.gov: Medicare Coverage Outside the United States (fact sheet, PDF); Kiplinger: Medicare and cruises, the 6-hour rule
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