is the spirit of tasmania rough

Short answer: sometimes. The Spirit of Tasmania crosses the Bass Strait, which can get frisky when cold fronts roll through; summer is usually kinder, winter can be lumpy. The ships are big ferries with stabilisers and the trip takes about 9–11 hours, so most crossings are fine, but you’ll feel motion on rough days. Book a cabin midships on a lower deck, eat light, and take motion-sickness meds if you’re prone.

Check forecasts before sailing and allow for delays or reschedules when the weather gets feisty—safety trumps punctuality. In short: not a rollercoaster, not a millpond—just proper sea travel with the occasional boogie.