Carnival shares dropped 8.6% to $43.95 Thursday.
The company expects the recent jump in fuel prices to cut profit by 8 cents a share.
Carnival also said weather-related disruptions, tensions in the Arabian Gulf and a ship-delivery delay are expected to cut 4 cents to 6 cents a share.
The fiscal year's adjusted earnings now should range $4.23 to $4.27 a share versus Carnival's previous guidance of $4.25 to $4.35. Analysts surveyed by FactSet were expecting $4.33 a share.
For the third quarter ended Aug. 31 the company reported adjusted earnings of $2.63 a share on revenue of $6.5 billion.
Analysts were expecting $2.53 a share on revenue of $6.16 billion.