Do you get jet lag on cruise ship?

You can not get jet lag on any kind of ship.

Jet lag is cause by rapidly crossing more than two time zones (in general) east-west or west-east, which throws off people's internal circadian clock and causes fatigue and other symptoms.

Neither ships nor automobiles travel fast enough to cause jet lag. The number of days these methods of travel take to cross more than two time zones allows people's internal clock to adjust to local time as they travel.