Shares of the company rose about 3 percent to $68.90 in early trading on Thursday.
Net revenue yields, a keenly watched metric that measures spending per available berth, climbed 3.9 percent on a constant currency basis, well above the company's estimate of 1.5 to 2.5 percent.
Carnival has benefited from a recent spurt in interest in cruising, as customers prefer to spend more on experiences such as travel, instead of buying clothes and accessories.
The company said it now expects adjusted earnings of $4.20 to $4.40 per shares for 2018, compared with $4.00 to $4.30 per share estimated previously.
Net income attributable to Carnival shareholders rose to $391 million, or 54 per share, in the quarter ended Feb. 28 from $352 million, or 48 cents per share, a year earlier.
Carnival's net revenue jumped 11.6 percent to $4.23 billion, above analysts' estimate of $4.11 billion.
Excluding items, it earned 52 cents per share, topping 43 cents per share estimated by analysts, according to Thomson Reuters I/B/E/S.