Royal Caribbean Cruises Ltd posted above-forecast second-quarter earnings and increased its 2010 earnings guidance due to stable bookings and improved cost control, boosting its shares.

Royal Caribbean's bigger rival, Miami-based Carnival Corp & Plc , last month projected a weak third quarter due to costlier fuel and volatile foreign exchange rates, hitting shares of both cruise operators.

Business conditions have remained on target in each of the company's main markets while improved cost control has enabled the company to raise its earnings guidance for the year, Royal Caribbean said in a statement.

Operating costs were lower than expected due mainly to strong cost control, energy conservation measures, expense timing and currency fluctuations, it added.

CEO Richard Fein said: Despite ongoing uncertainty with the economy, our profitability continues to improve and our booking environment continues to be remarkably stable.

Shares in Royal Caribbean jumped on the announcement and are up 5.6 percent to 165 Norwegian crowns in Oslo trade. Trading in New York resumes later on Thursday.

(Reporting by Oslo newsroom)