Navalyze · Cruise · Ship

COSTA DIADEMA

IMO: 9636888
Type: Passenger ship (Cruise Passenger ship)
Flag (estimated): Italy
Port of registry: Genoa
Technical efficiency: EEXI 8.28 g CO₂/t·nm

ISM company (DoC holder) in 2025: Costa Crociere S.p.A. · part of Carnival Corporation

Report year

2022 at a glance

From the 2022 THETIS-MRV report.

Fuel kg/nm

357

Passenger median 250 kg/nm (+43%)

CO₂ per transport work (pax)

544

g CO₂/pax·nm · Passenger median 831 (−34%)

Average speed

15.4 kn

Passenger median 12.1 kn (+27%)

Fuel per day at sea

131.7 t/day

Fuel consumed

20,254 t

CO₂ emitted

63,655 t

Distance sailed

56,817 nm

CO₂ ÷ CO₂ per mile

Time at sea

3,690 h

154 days, 42% of the year

Within the cruise fleet, 2025

Set against all 202 cruise ships with a full-year 2025 report. Bigger ships burn more per mile but less per tonne of cargo, so read fuel per mile with the ship's size in mind.

Fuel kg/nmThis ship 335 kg/nm · median 264 (+27%)

89.6Ranks 137 of 202, lowest first416

Average speedThis ship 15.2 kn · median 13.1 (+16%)

10.8Faster than 86% of cruise ships15.5

CO₂ per transport work (pax)This ship 292 g CO₂/pax·nm · median 521 (−44%)

303Ranks 20 of 202, lowest first1,701

Middle 80% of shipsMiddle 50%Cruise medianThis ship

Where the emissions happen, 2022

THETIS splits each ship's CO₂ by voyage type. The split sets how much falls under the EU ETS: all of it within the EU and at berth, half of it on voyages into or out of the EU.

Between EU ports77%
From the EU3%
Into the EU10%
At berth in the EU10%

Fuel burned laden

–

Not reported

CO₂ at berth

6,155 t

9.7% of the ship's CO₂, alongside in EU ports

Methane (CH₄)

–

Mainly from LNG; small for oil, biofuel and methanol

CO₂eq uplift

–

CO₂eq on top of CO₂ alone, from CH₄ and N₂O

Over the years

Full-year reports only. The Cruise median is the middle ship of all cruise ships reporting that year; it moves with the fleet, so a ship can gain on it without changing itself.

Fuel kg/nm

COSTA DIADEMA
Cruise median

200.0400.0600.0800.01,0001,200

’182018’192019’202020’212021’222022’232023’242024’252025

Average speed, kn

COSTA DIADEMA
Cruise median

0.05.010.015.020.0

’182018’192019’202020’212021’222022’232023’242024’252025

CO₂ per transport work (pax), g CO₂/pax·nm

COSTA DIADEMA
Cruise median

0.05001,0001,5002,000

’182018’192019’202020’212021’222022’232023’242024’252025

Year on year

Year	Average speed	Fuel kg/nm	Fuel per day at sea	Distance	CO₂ per transport work	Reading
2024→2025	−0.2 kn	−2%	−4%	−23%	+3%	Same speed, fuel per mile down 2%; in line with the speed change.
2023→2024	+1.3 kn	−13%	−5%	+12%	−18%	1.3 kn faster, fuel per mile down 13%; better than speed alone explains (hull, engine or trade).
2022→2023	−1.3 kn	+11%	+1%	−1%	−36%	1.3 kn slower, fuel per mile up 11%; worse than speed alone explains (fouling, weather, loading or trade).
2021→2022	+3.0 kn	−41%	−27%	+138%	−68%	3.0 kn faster, fuel per mile down 41%; better than speed alone explains (hull, engine or trade).
2020→2021	+11.1 kn	−42%	+464%	+246%	+405%	11.1 kn faster, fuel per mile down 42%; better than speed alone explains (hull, engine or trade).
2019→2020	−12.7 kn	+192%	−73%	−89%	+22%	12.7 kn slower, fuel per mile up 192%; worse than speed alone explains (fouling, weather, loading or trade).
2018→2019	+2.7 kn	−11%	+11%	−9%	−6%	2.7 kn faster, fuel per mile down 11%; better than speed alone explains (hull, engine or trade).

Fuel per mile rises roughly with the square of speed for a given ship, so a change in speed explains much of a change in fuel per mile.

Every reporting year

One row per THETIS-MRV report. A ship that changed operator during a year has a part-year report for each.

Operation

Year	ISM company	Fuel t	CO₂ t	Distance nm	Hours at seah	Average speedknots at sea	Fuel kg/nmthis ship	CO₂ per transport work (cargo)g/t·nm, this ship	Laden fuel
2025	Costa Crociere S.p.A.	16,198	51,086	48,414	3,177	15.2	335	–	–
2024	Costa Crociere S.p.A.	21,476	67,475	62,700	4,061	15.4	343	–	–
2023	not published	22,062	69,301	55,968	3,976	14.1	394	–	–
2022	not published	20,254	63,655	56,817	3,690	15.4	357	–	–
2021	not published	14,433	45,423	23,858	1,925	12.4	605	–	–
2020	not published	7,175	22,532	6,900	5,404	1.3	1,040	–	–
2019	not published	23,330	72,923	65,434	4,658	14.0	357	–	–
2018	not published	28,757	89,733	71,956	6,349	11.3	400	–	–

Benchmark and verification

Year	ISM company	CO₂ per TW, g CO₂/pax·nm	Cruise median	vs Cruise	Rank	Verifier	Methods
2025	Costa Crociere S.p.A.	292	521	−44%	20 of 202	DNV	B
2024	Costa Crociere S.p.A.	285	618	−54%	15 of 202	DNV	B
2023	not published	346	625	−45%	23 of 202	DNV	B
2022	not published	544	831	−34%	34 of 187	RINA	A
2021	not published	1,704	1,315	+30%	59 of 100	RINA	A
2020	not published	337	1,169	−71%	11 of 100	RINA	A
2019	not published	276	589	−53%	4 of 177	RINA	A
2018	not published	293	577	−49%	6 of 153	RINA	–

Fuel per mile and CO₂ per tonne-mile are the ship's own reported KPIs. Cruise ships are benchmarked on CO₂ per transport work (pax) (TW), in g CO₂/pax·nm. CO₂eq adds methane and nitrous oxide and is in the public files from 2024. Rank counts from the lowest figure among that year's cruise ships. Methods: A delivery notes, B tank monitoring, C flow meters, D direct measurement. FuelEU GHG intensity is not shown: it needs fuel types, which the public file does not carry. Operators are named only from 2024, the first year the public files carry them; earlier years belong to the ship, not to any company.