Best cruises for young adults looking for adventure in 2021

1. P&O Cruises

P&O breaks up its cruises into six categories – Sea Australia, Sea Asia, Main Events, Islands, Sea Breaks and Explorer – to help you find that perfect sailing.

The secret to picking the young adult-skewed cruise is in the itinerary. You'll generally find young adult workers on shorter and more adventurous trips, so hit up the Main Events, Sea Breaks or Explorer cruises for sailors of similar ages.

• Young adult activities: Adults-only comedy club, bars and nightclubs, casino and adults-only ocean bar.
• Adults-only sundeck? Called The Oasis, this 18+ sundeck is a child-free area with a pool, hanging chairs and cushioned cabanas. It's available on the Pacific Aria and Pacific Eden.

2. Carnival Cruise Lines

Carnival has developed a reputation for itself for being a "fun" cruise line with a lively feel at a good price.

Sure, there will be kids onboard as Carnival has one of the best activity playgrounds on the ocean, but if you don't want to join them on the rope walks and water slides, there are adults-only sunning areas to hide in.

• Young adult activities: Clubs, bars, casinos and nightclubbing.
• Adults-only sundeck? The adults-only sundeck Serenity can be found fleet-wide apart from on Carnival Conquest and Carnival Triumph. You need to be 18 years or older to access it on sailings from Australia. It features loungers, hammocks and umbrellas.

3. Celebrity Cruises

This premium cruise line has a premium lineup of activities to keep you relaxed and entertained throughout your sailing.

If you're the kind who'd rather unwind in the lap of luxury rather than stay up all night dancing under the stars, Celebrity Cruises will primp and prime you. Its Solstice Class is a more sophisticated ship that draws a good 20-30-something crowd.

• Young adult activities: Spa, health and beauty seminars, fitness classes, martini bar, casino, partner dance classes, nightclub and mixology classes.
• Adults-only sundeck? The Solarium is where to go to get away from the youngsters. It's the onboard adults-only pool area.

4. Contiki's sailing trips

Specialising in unforgettable journeys in Europe, Asia, Latin America, the USA and more for 18-35 year olds, Contiki's small-boat trips are not to be overlooked.

• Young adult activities: Snorkelling, sailing, hiking and kayaking.
• Adults-only sundeck? No. However, independent travellers must be at least 18 years.

5. Norwegian Cruise Line

When it comes to ideal entertainment for young adults, Norwegian Cruise Line is on point.

From music-themed cruises that feature chart-toppers to casinos on the ocean, your journey will fly by with all the activities this line has prepared for millennials. Those travelling on their own can even book a single room.

• Young adult activities: Live music, casinos, clubs, bars, spa, White Hot Party and ice bars on some ships.
• Adults-only sundeck? Norwegian Epic, Breakaway, Getaway and Escape all have adults-only sanctuaries that have hot tubs, loungers and a water feature. In the evenings on Epic, Breakaway and Getaway the area becomes an open-air nightclub.

6. Royal Caribbean

Famed for owning the world's largest cruise ships, the party scene is hot on a Royal Caribbean cruise.

Day or night you'll feel the buzz of excitement on your Royal Caribbean ship. The fleet features some of the most innovative activities on the ocean including a skydive simulator on the Quantum-class ships, the ice rinks on the Voyager-class.

• Young adult activities: Rock climbing, casino, live music, skydive and surfing simulators, bars and clubbing.
• Adults-only sundeck? The Solarium is Royal Caribbean's adults-only retreat and pool area. In the evenings it transforms into a fine dining destination. At certain hours, it may be used by under-16 year olds with parental supervision.

7. G Adventures' sailing trips

With tours for the budget conscious, G Adventures calls to like-minded and aged travellers from around the world with its marine adventures.

Naturally, the destinations this company cruises to are just as adventurous as the folk who embark on its ships. G Adventures' marine tours include sailings in the Galapagos Islands, Greek Isles, Cuban Coast, Antarctica and the Arctic.

• Young adult activities: Snorkelling, sailing, hiking and kayaking.
• Adults-only sundeck? No. However, independent travellers must be at least 18 years old. On non-family tours, children over 12 are permitted with an accompanying adult.

8. Topdeck's sailing trips

Catering to the 18-30s crowd, Topdeck knows how difficult it can be to budget for a life-changing adventure.

• Young adult activities: Snorkelling, sailing, hiking and kayaking.
• Adults-only sundeck? No. However, independent travellers must be at least 18 years.

9. MSC Cruises

Cash in on your youth with MSC Cruises. It offers discounts for 18-29 year olds. No joke.

If you thought that your youth discounts stopped when you turned 18, think again. MSC Cruises encourages young passengers by offering them discounts per cabin for couples and groups. Better get the gang together.

• Young adult activities: Bars, spa, fitness centre, shopping, live music and theatre shows.
• Adults-only sundeck? Called the Top 18, this is located on the 18th deck of the Fantasia-class ships and features spa services, bar and relaxation pods.

10. U River Cruises

A reimagined river cruise that is part boutique hotel, part private yacht and part local hotspot.

From international DJs to silent discos, mixology classes to farm-to-table cuisine and rooftop yoga on the sun deck, this is the one cruise line that is specifically tailored for millennial cruisers.

• Young adult activities: Biking, canal cruises, hiking, rock climbing, wine tasting, street art walks, kayaking, bars and clubbing.
• Adults-only sundeck? The Rooftop Lounge is an open-air hangout perfect to relax and take in the views during the day and the Ice Bar is where you'll head when it gets dark for all the night time action.

11. Travel Talk

Tailored for the 18-39 crew, small groups tours give you the experience of a lifetime without breaking the bank.

Experience the high seas on a modern pirate ship in Croatia or traditional Turkish gulet as you explore everything the region has to offer.

• Young adult activities: Rafting, ziplining, hot-air ballooning, bars and onboard parties.
• Adults-only sundeck? Most ships have at least two decks and a sundeck with sunbeds and chairs.

12. Intrepid's Sailing Trips (via TourRadar)

Set sail in Europe, the Caribbean or Asia where you can help navigate or sit back and relax.

Intrepid's unique small group tours means that you can make new friends as you explore the world by sea.

• Young adult activities: Hiking, rowing, swimming and snorkelling.
• Adults-only sundeck? No. However, independent travellers must be at least 18 and the minimum age is 15.