Let's look at some of the many things you can do for "free" on large, mainstream cruise ships.
Eat and DrinkMeals in the main restaurant and buffets are included in the cruise fare for all ships. You can always get three or more "free" meals a day, along with snacks, some of which are offered 24-hours per day. Coffee, tea, and water (not bottled) are also included, and the tap water is always drinkable on large ships. Considering that ships are feeding thousands of meals per day, the food is very good, with multiple courses and choices.
Although most mainstream ships now feature specialty restaurants at an extra fee, the variety offered in the dining room and buffets is sufficient for most travelers.
Note that some luxury ships include the specialty restaurants, alcohol, and soft drinks in their base fares, so they are more "all-inclusive".
Enjoy the Onboard EntertainmnentCruise ships have at least one show every evening in the main lounge. Large cruise ships often have Las Vegas-style revues, with singers, dancers, and amazing sets and costumes. In addition to the main lounge shows, passengers can enjoy piano bars, small combos, and music of all types in the multiple lounges most ships have.
The entertainment does not stop with music. Most ships feature comedians, magicians, and even ventriloquists at some of the shows. All of this entertainment is included in your fare.
For those who want to participate in the entertainment, ships have karaoke, talent shows, and ballroom and disco dancing.
Exercise in the Fitness Center or Walk/Jog Around the DeckCruise ships have modern fitness centers with treadmills, weights, ellipticals, bicycles, and other exercise equipment that are equal to (or better than) you would find at home. Use of the fitness center is free, but some classes such as yoga or Pilates are fee-based.
A workout sure is much more enjoyable when you have a great view of the ocean. In addition to the fitness center, most ships have either a promenade deck that wraps around the ship or a deck with a walking/jogging track.
Swim in the PoolCruise ships always have one or more swimming pools that are free. These pools are often small when compared to those at a resort, but they can still be fun for all ages. Ship passengers can also enjoy water volleyball or other pool games. Many ships have separate pools for adults, kids, and even teens.
If swimming sounds like too much work, cruise ships also feature hot tubs where you can soak those tired muscles.
Sit in the Sun by the PoolSitting in the sun or the shade with a good book is a favorite onboard activity for many cruise passengers. There's something special about the sea breeze and the sea air. Like the swimming pool, use of the lounge chairs is free.
Watch a MovieMost cruise ships feature movies on the TVs in the cabins. However, watching a movie on a large outdoor screen by the pool is great fun. These outdoor movies are shown "under the stars' and great free fun on a ship. Some ships also have indoor movie theaters where movies are shown throughout the day.
Read a Book in the LibraryAll cruise ships have onboard libraries. Some are very tiny, but most are adequate and have space to sit and read a good book. You can also check out the books and take them back to your cabin or out on the deck to read.
Explore the ShipLarge cruise ships are engineering marvels, and taking the time to explore the decks of a ship is a fun way to spend time onboard. Ships also sometimes have free galley tours, which offer passengers the opportunity to see some of the secrets of creating thousands of meals each day in relatively small spaces.
When exploring the ship, be sure to peek into the numerous onboard shops. You can look for free, but don't be tempted to buy if you are trying to stay on budget!
Play Some GamesShips often have onboard game tournaments with no participation fees, (i.e. free). These tournaments include basketball, miniature golf, shuffleboard, ping pong, and a variety of other games. In addition to being free, the players usually get points that can be accumulated and exchanged for small gifts at the end of the cruise.
The Celebrity Solstice class ships feature croquet or bocce ball games at the Lawn Club.