Is the Tasman Sea rough? What to expect on the crossing
Yes, the Tasman Sea is commonly reported as rough, but the difficulty here is duration rather than intensity. A cruise crossing takes two to three days at sea with no land to duck behind at any point. Bass Strait can be violent for a single night; the Tasman is more often moderate motion that simply does not stop.
Sea · South-west Pacific · Reputation among passengers: has a long-standing reputation for rough passages.
2,000 km of unbroken westerly fetch
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Why the Tasman Sea gets rough
The Tasman is about 2,000 km across, and its southern half lies under the Roaring Forties. Westerly depressions track through unobstructed, so swell builds over a very long fetch before it reaches you. There is also nothing to break it: no island chain, no headland, nothing between Australia and New Zealand at those latitudes. The East Australian Current runs warm water south down the Australian side, and where a southerly change runs against it the sea steepens quickly, which is why the Australian end of the crossing is often the lumpiest part.
When it's worst, month by month
Roughly November to March is the fairer half of the year, with lighter and more variable winds over the northern Tasman. April to October is when the westerlies strengthen and depressions come through more often, so gales are more likely. Southern routings feel Southern Ocean swell year-round, which is why a leg towards Fiordland can be lumpier than a northern one.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Mixed | Mixed | Mixed | Rough | Rough | Roughest | Roughest | Roughest | Rough | Rough | Mixed | Mixed |
Typical seasonal pattern, not a forecast — any month can deliver a calm crossing or a bad one. Check the marine forecast for your sailing date.
Where to be on board
Roughest stretch: Nearly all of it; there is no sheltered section
Midship on a low passenger deck. Over two or three days the difference between decks compounds.
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The crossings that cross it
| Route | Typical duration | What to know |
|---|---|---|
| Sydney–Auckland | 2–3 days at sea | The open Tasman leg of trans-Tasman and repositioning cruise itineraries. |
| Auckland–Sydney | 2–3 days at sea | Westbound version, usually placed at the end of a New Zealand itinerary. |
| Hobart–Fiordland or Dunedin | About 2–3 days at sea | The southern routing, closest to the Roaring Forties and the Southern Ocean swell. |
What helps on this crossing
- Think of it as days, not hours. Set a routine of sleep, meals and fresh air on deck, because the motion will still be there tomorrow.
- Most people settle after the first day or so at sea. The Tasman is long enough for that to actually help, unlike a short ferry hop.
- Book midship on a low deck. Over 48 to 72 hours, the extra movement of a high forward cabin adds up rather than passing quickly.
- Southern legs towards Fiordland and Dunedin take swell straight off the Southern Ocean. A northern routing into Auckland is generally the easier one.
- Go outside regularly. On a multi-day crossing, staying in a windowless cabin for a whole day tends to make things worse rather than better.
- The ship's daily programme usually flags the expected sea state for the next day. Use it to plan when to eat and when to rest.
For the full toolkit see the seasickness guide, or what to do once it has already started.
Frequently asked questions
Is the Tasman Sea rough?+
It has a strong reputation for it, and the southern half genuinely sits in the westerly wind belt. Conditions vary a great deal by season and by how far south the ship routes. The thing passengers most often describe is not one dramatic day but continuous movement over several days, which is a different kind of tiring.
How long does it take to cross the Tasman Sea by ship?+
Two to three days at sea for a typical cruise crossing between eastern Australia and New Zealand. The sea is about 2,000 km wide, and the direct Sydney–Auckland route is roughly 1,160 nautical miles. Longer itineraries break the crossing with Tasmanian or South Island ports, which shortens each individual open-water stretch.
Is the Tasman Sea rougher than Bass Strait?+
They are rough in different ways. Bass Strait is shallow, so its waves are steeper and shorter, and a bad night there can be more violent. The Tasman is deep and open, so the swell is longer, but you are exposed to it for two or three days with nowhere to shelter. Duration is the Tasman's problem.
When is the best time to cross the Tasman Sea?+
The southern summer, roughly November to March, brings fairer weather and lighter winds, and is when most trans-Tasman itineraries run. April to October brings stronger westerlies and more frequent depressions. Weather in the Tasman is variable at any time of year, so a settled forecast matters more than the month.
Where should I book a cabin for a Tasman Sea crossing?+
Low down and near the middle of the ship, where pitch and roll are least. On a crossing measured in days rather than hours, that choice is worth more than it would be on a short ferry. An outside cabin or easy deck access also helps, because seeing the horizon is easier than guessing at the motion.
Other crossings
Sources & further reading
- https://en.wikipedia.org/wiki/Tasman_Sea
- https://www.vikingcruises.com/oceans/cruise-destinations/asia-australia/australia-new-zealand/index.html
- https://www.nz-tourism.com/cruise-from-sydney-to-new-zealand/
- https://www.bom.gov.au/australia/charts/viewer/index.shtml?type=mslp-precip&tz=AEDT&area=Aus&model=access-g
Explore more
Sea conditions described here are typical patterns drawn from published marine and operator information as of July 2026, not a forecast — conditions on any given sailing depend on the weather that day, and any month can deliver a calm crossing or a bad one. Route and operator names are trademarks of their respective owners; Dizzout is not affiliated with or endorsed by them. Seasickness sensitivity varies from person to person; this page is informational and not medical advice.