This is according to Similarweb, the digital intelligence platform.
Across the board growth
Similarweb found traffic was up year-over-year for all the lines in its cruise coverage, with an aggregate 15.6% increase.
Some brands stood out.
Virgin Voyages' growth story continued in May, with a 104.8% year-over-year traffic increase. Compared to April, Virgin’s web traffic rose 20%. The line attracted 2.2m visits in May, according to Similarweb estimates.
Celebrity Cruises drew 5m visits, up 36.8% year-over-year, while sister brand Royal Caribbean International attracted 13.6m visits, up 4.5% from a year ago.
Carnival Cruise Line got 14.4m visits, up 5.9%, and Norwegian Cruise Line, 8.9m visits, a 33% increase.
Web traffic to Princess Cruises (7.2m) grew 15% from May last year, while Holland America Line traffic (5.4m) was up 13.2%.
April to May changes
Similarweb's David Carr, senior insights manager, said the cruise brands also saw month-over-month growth with summer's approach, apart from Princess Cruises, where traffic was down a fraction of a percent.
The biggest monthly gainer in traffic share was NCL, up 2.1 percentage points. Virgin gained 1.7 points and Celebrity 1.4. Royal Caribbean's share was down 2.5 points and Carnival’s down 2.3 points.
According to Similarweb, Carnival and Royal Caribbean draw nearly as much traffic as all the other competitors combined, which is why gains by any of the other brands tend to come at their expense. That makes NCL the biggest competitor to have also seen a big increase in May.
For further insights, see Carr's Similarweb blog post.