Side-by-side cruise ship comparison · Updated February 2026
across 5 categories
Size
Based on gross tonnage and length
Capacity
Based on passengers and crew
Modernity
Based on year built
Service
Based on passenger-to-crew ratio (lower is better)
Spaciousness
Based on gross tonnage per passenger (higher is better)
Costa Diadema
Costa Serena
Gross Tonnage
Costa Diadema
132,500 GT
Costa Serena
114,500 GT
Length
Costa Diadema
306 m
Costa Serena
290 m
Beam
Costa Diadema
37 m
Costa Serena
35.5 m
Passengers
Costa Diadema
3,724
Costa Serena
3,780
Crew
Costa Diadema
1,253
Costa Serena
1,100
Decks
Costa Diadema
—
Costa Serena
14
Year Built
Costa Diadema
2,014
Costa Serena
2,007
Space Ratio
Costa Diadema
35.6 GT/pax
Costa Serena
30.3 GT/pax
Passenger:Crew Ratio
Costa Diadema
2.97 :1
Costa Serena
3.44 :1
| Specification | Costa Diadema | Costa Serena |
|---|---|---|
| Overview | ||
| Cruise Line | Costa Cruises | Costa Cruises |
| Class | Diadema Class | Concordia Class |
| Status | active | active |
| Year Built | 2,014Winner | 2,007 |
| Dimensions | ||
| Gross Tonnage | 132,500 GTWinner | 114,500 GT |
| Length | 306 mWinner | 290 m |
| Beam | 37 mWinner | |
| Capacity | ||
| Passengers | 3,724 | 3,780Winner |
| Crew | 1,253Winner | 1,100 |
| Key Ratios | ||
| Space Ratio | 35.6 GT/paxWinner | 30.3 GT/pax |
| Passenger:Crew Ratio | 2.97:1Winner | 3.44:1 |
| Build | ||
| Builder | Fincantieri | Fincantieri |
| Flag | Italy | Italy |
| IMO Number | 9636588 | Tf1ba6e887 |
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 |
Bottom line: Costa Diadema wins more categories (5 vs 0), making it the stronger all-round choice based on current data.
Costa Diadema
Large 3,724-guest capacity offers competitive pricing
Well-suited for cruise newcomers
3,724 passengers means tons of activities
Comfortable atmosphere for two
Costa Serena
Well-suited for cruise newcomers
Large 3,780-guest capacity offers competitive pricing
3,780 passengers means tons of activities
Comfortable atmosphere for two
Free cancellation on most rooms
Bundle & save on your cruise trip
Medical, trip cancellation & luggage cover
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35.5 m |
| Draft | 8.5 mWinner | 8.3 m |
| Decks | — | 14 |
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