Costa Cruises
Costa Diadema
- Cruises
- 73
- From
- $490
Ship comparison
Costa Diadema vs Star of the Seas
Royal Caribbean
Star of the Seas
- Cruises
- 17
- From
- $897
The verdict
Which should you choose?
Costa Diadema is a mega Costa Cruises ship carrying 4,947 passengers, in service since 2014. Star of the Seas is a mega Royal Caribbean ship carrying 5,610 passengers, in service since 2025.
Choose Costa Diadema if you want a lower starting fare, better-rated dining or more cruises to choose from: it outscores Star of the Seas for dining (7.0 vs 6.0) in Cruiseable’s Bliss scores, its cruises start from $490 (vs $897) and it has 73 cruises on sale (vs 17).
Choose Star of the Seas if you want more space per passenger, more crew per passenger or a newer ship: it has 44.7 gross tons per passenger (vs 26.8), it has a crew member for every 2.4 passengers (vs 3.9) and its maiden voyage was in 2025 (vs 2014).
Side by side
Specifications
marks the better figure where more, or less, is plainly better.
| Costa Diadema | Star of the Seas | |
|---|---|---|
| Cruise line | Costa Cruises | Royal Caribbean |
| Ship size | Mega | Mega |
| Maiden voyagenewer highlighted | 2014 | 2025 (better) |
| Gross tonnage | 132,500 | 250,800 |
| Passengers | 4,947 | 5,610 |
| Crew | 1,253 | 2,350 |
| Passengers per crew memberfewer is better | 3.9 | 2.4 (better) |
| Space per passengergross tons per passenger; more is roomier | 26.8 | 44.7 (better) |
| Decks | 20 | 14 |
| Length | 1,004 ft | 1,196 ft |
| Beam | 122 ft | 219 ft |
| Speed | — | 25 mph |
| Cruiseable ratingout of 10 | 8 / 10 | — |
| Cruises on sale | 73 | 17 |
| Upcoming sailings | 143 | 76 |
| Cruise lengths | 2 to 27 nights | 7 nights |
| Fares fromlower highlighted | $490 (better) | $897 |
Bliss scores
How they rate, out of 10
Cruiseable rates ships out of 10 on ten parts of a cruise holiday. Costa Diadema leads on 1 of the ten, Star of the Seas on 4, with 5 level.
- Active
- Adventure & nature
- Cultural
- Dining
- Entertainment
- Family friendly
- Party
- Romantic
- Spa & fitness
- Staterooms
Costa Cruises
Costa Diadema
Sailing now
73 cruises on sale, from $490.
Royal Caribbean
Star of the Seas
Star of the Seas from Royal Caribbean is basically a floating resort on a scale that rewrites what “big ship” means.
Sailing now
17 cruises on sale, from $897.
Questions
Costa Diadema or Star of the Seas?
Which is bigger, Costa Diadema or Star of the Seas?
Star of the Seas is bigger at 250,800 gross tons, against 132,500 gross tons for Costa Diadema. Costa Diadema carries 4,947 passengers and Star of the Seas carries 5,610.
Which ship is newer, Costa Diadema or Star of the Seas?
Star of the Seas is newer, with a maiden voyage in 2025 against 2014 for Costa Diadema.
Which has more space per passenger?
Star of the Seas, with 44.7 gross tons per passenger against 26.8 on Costa Diadema. The higher the figure, the more ship there is for each guest.
Which has more crew per passenger?
Star of the Seas, with one crew member for every 2.4 passengers against one for every 3.9 on Costa Diadema.
Which is better for families?
They score the same for family friendliness in Cruiseable’s Bliss scores: 8.0 out of 10.
Still deciding?
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