Norwegian Cruise Line Holdings' third-quarter earnings improved to its highest level ever, thanks to a busy summer season for its passengerships.

The Frank del Rio-led company posted adjusted net income of $506.4m versus a $427m profit a year earlier.

Earnings per share came in at $2.11, up from $1.74 during the same period last year but shy of analyst estimates of $2.21 EPS.

Revenue gained 12.5% to a record $1.9bn, driven by strong demand for peak summer season sailings, particularly in Alaska and Europe, the company said.

“As 2018 winds down, our earnings outlook improves as we increase our full year adjusted EPS above the high-end of our previous guidance range,”said Mark Kempa, executive vice president and chief financial officer.

Royal Caribbean said it expects to hit record earnings in full year 2018 and has risen its full-year adjusted EPS guidance to $4.85.

Chief executive Frank del Rio said a "robust booking environment" should translate into positive momentum for double-digit EPS and return on invested capital through 2020.