Spots going fastCosta Diadema vs Costa Serena
Side-by-side cruise ship comparison · Updated February 2026
Costa Diadema is the larger vessel at 132,500 GT — 16% more than Costa Serena's 114,500 GT. Costa Diadema offers more personal space with a space ratio of 35.6 GT per passenger versus 30.3. Built in 2014, Costa Diadema is 7 years newer — an advantage for travellers seeking modern amenities and design.
Score: 7 – 0
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Category
Costa Diadema
Costa Serena
Size
132,500 GT
114,500 GT
Passengers
3,724
3,780
Year Built
2014
2007
Crew Ratio
1:3.0
1:3.4
Space Ratio
35.6
30.3
Decks
—
14
Length
306m
290m
From Price
$1,997/pp
$260.3/pp
Comparison Verdict
Costa Diadema is the larger vessel at 132,500 GT — 16% more than Costa Serena's 114,500 GT. Costa Diadema offers more personal space with a space ratio of 35.6 GT per passenger versus 30.3. Built in 2014, Costa Diadema is 7 years newer — an advantage for travellers seeking modern amenities and design.
| Category | Winner |
|---|---|
| Size | Costa Diadema |
| Capacity | Costa Diadema |
| Modernity | Costa Diadema |
| Service | Costa Diadema |
| Spaciousness | Costa Diadema |
| Decks | Tie |
| Length | Costa Diadema |
| Fleet Power | Costa Diadema |
Bottom line: Costa Diadema leads 7–0 across our categories — strongest in Size. Choose Costa Diadema for overall superiority; pick Costa Serena if its strengths matter more to you.
Which Ship Is Right for You?
Choose Costa Diadema if...
- You want the newer ship (built 2014, 7yr newer)
- Size matters to you (132,500 GT)
- Better service ratio (3.0:1 crew ratio)
- More space per guest (35.6 GT/pax)
Choose Costa Serena if...
- More onboard variety (3,780 guests)
- Save $1,736.7/person on sailings
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Frequently Asked Questions
How is the comparison score calculated?
We compute scores across 8 categories using real spec data — gross tonnage, passenger capacity, crew capacity, year built, length, deck count, space ratio, and fleet power. Each category awards one point to the winning ship.
What is the space ratio and why does it matter?
Space ratio is gross tonnage divided by passenger capacity. A higher number means more space per guest. Luxury lines typically score above 40; mass-market ships often fall in the 30-40 range.
What does the passenger-to-crew ratio mean?
Passengers per crew member. Lower is better — more staff per guest means better service. Luxury lines aim below 2:1; large mainstream ships may be 3-4:1.
Are the prices shown accurate?
Prices are sourced from Cruisebound and reflect real-time availability. They may change based on cabin type, date, and demand. Click through to see the latest fares.
Can I compare more than two ships?
Yes — up to four ships. Use the search tool on the compare hub page to add additional ships.
How current is the ship data?
Specifications come from our database of 380+ vessels, revalidated every 5 minutes via ISR. The "Updated" timestamp shows when records were last modified.
