Nausea Index: sea crossings

The roughest sea crossings, ranked

Every sea and crossing in our guides carries a roughness rating built from its geography, its weather patterns and what passengers consistently report. This table puts all of them in one list, roughest first, with the mechanism that makes each one move.

This cut of the Dizzout Nausea Index ranks 128 sea crossings. 6 entries sit in the top band, rated notorious: Bering Sea, Drake Passage, Foveaux Strait and 3 more. Every rating is the one already published in the entry's own Dizzout guide, so a row summarizes a full guide, not a lab test.

Tap a column heading to re-sort, and open any crossing for its full guide: the rough season, the routes that cross it, and what helps once you are on board.

Rank
1	Bering Sea	Alaska	Sea	Notorious 92	Aleutian Low storms over a wide deep basin
1	Drake Passage	Southern Ocean	Passage	Notorious 92	No land to stop wind, swell or current
1	Foveaux Strait	Southern New Zealand	Strait	Notorious 92	Roaring Forties swell over a shallow seaway
1	Gulf of Penas	Chilean Patagonia	Gulf	Notorious 92	Open Pacific, westerly storms
1	Hecate Strait	British Columbia	Strait	Notorious 92	Shallow strait, steep wind waves, southeast gales
1	Pentland Firth	Northern Scotland	Firth	Notorious 92	Tidal races, not wind-driven waves
7	Backstairs Passage	South Australia	Passage	Rough 75	Narrow tidal channel, Southern Ocean wind
7	Badung Strait	Bali, Indonesia	Strait	Rough 75	Strong tidal flow, monsoon wind and swell
7	Barents Sea	Arctic Norway	Marginal sea	Rough 75	Open Arctic water, winter polar lows
7	Bass Strait	Southern Australia	Strait	Rough 75	Ocean swell shortening over a 60 m shelf
7	Bay of Biscay	North-east Atlantic	Bay	Rough 75	Atlantic swell over a shoaling shelf
7	Bristol Channel	South-west England and Wales	Channel	Rough 75	Atlantic swell and a 13 m tidal range
7	Cabot Strait	Atlantic Canada	Strait	Rough 75	Atlantic storm track across an open gulf mouth
7	Celtic Sea	Between Ireland, Cornwall and Brittany	Sea	Rough 75	Open Atlantic swell over a shelf sea
7	Cook Strait	New Zealand	Strait	Rough 75	Wind against a 5-knot tidal stream
7	East China Sea	Southern Japan	Sea	Rough 75	Typhoons and fronts over a shallow sea
7	Galápagos Islands	Ecuador	Archipelago	Rough 75	Open-ocean swell, small fast boats
7	German Bight	North Sea coast of Germany	Bight	Rough 75	Shallow open bight with tidal channels
7	Great Australian Bight	Southern Australia	Bight	Rough 75	Southern Ocean swell with unlimited fetch
7	Gulf of Alaska	North Pacific	Gulf	Rough 75	Aleutian Low storms, no island shelter
7	Gulf of Lion	Western Mediterranean	Gulf	Rough 75	Mistral funnelled down the Rhône valley
7	Gulf of Maine	Maine and Nova Scotia	Gulf	Rough 75	Open Atlantic gulf, winter gales on a long fetch
7	Gulf of St. Lawrence	Eastern Canada	Gulf	Rough 75	Open gulf, autumn wind waves, winter ice
7	Jeju Strait	South Korea	Strait	Rough 75	Winter wind over a strait between two seas
7	Lake Erie	Great Lakes (Ohio and Ontario)	Lake	Rough 75	Shallow lake, seas build fast
7	Lake Huron	Great Lakes (Ontario and Michigan)	Lake	Rough 75	Open fetch, winds from any quarter
7	Lake Michigan	US Midwest	Lake	Rough 75	Long fetch under autumn gales
7	Lake Superior	Great Lakes (Michigan, Minnesota, Wisconsin and Ontario)	Lake	Rough 75	Huge fetch over deep water
7	Lombok Strait	Bali and Lombok, Indonesia	Strait	Rough 75	Monsoon winds over open Indian Ocean water
7	Mozambique Channel	South-west Indian Ocean	Channel	Rough 75	Cyclone corridor feeding the Agulhas Current
7	North Sea	North-west Europe	Sea	Rough 75	Shallow basin, short steep wind chop
7	Norwegian Sea	Northern Europe	Sea	Rough 75	Ocean swell at unsheltered capes
7	Santa Barbara Channel	Southern California	Channel	Rough 75	Afternoon northwest wind along the islands' north shores
7	Sea of Japan	East Asia	Sea	Rough 75	Winter monsoon over a long open fetch
7	Sea of the Hebrides	West coast of Scotland	Sea	Rough 75	Partly sheltered sea with Atlantic storms in winter
7	South China Sea	Southeast Asia	Sea	Rough 75	Northeast monsoon wind over a deep, open sea
7	St George's Channel	Wales and Ireland	Channel	Rough 75	Channel linking the Celtic Sea and the Irish Sea
7	Strait of Belle Isle	Newfoundland and Labrador, and Quebec	Strait	Rough 75	Southwest Gulf swell, tidal current and ice
7	Strait of Bonifacio	Corsica and Sardinia	Strait	Rough 75	Mistral squeezed through an 11 km gap
7	Strait of Magellan	Southern Chile	Strait	Rough 75	Narrows, strong tide and wind
7	Taiwan Strait	Taiwan	Strait	Rough 75	Northeast monsoon over a shallow strait
7	Tasman Sea	South-west Pacific	Sea	Rough 75	2,000 km of unbroken westerly fetch
7	Tsugaru Strait	Japan	Strait	Rough 75	Winter monsoon seas into a 20 km gap
7	Vestfjorden	Northern Norway	Open fjord	Rough 75	Open bight of sea with strong tidal eddies
45	Adriatic Sea	Central Mediterranean	Sea	Manageable 50	Katabatic bora gusts off the Dinaric Alps
45	Aegean Sea	Eastern Mediterranean	Sea	Manageable 50	Summer meltemi funnelled down the Aegean
45	Alboran Sea	Spain and Morocco	Sea	Manageable 50	Open water, roughest from winter to spring
45	Andaman Sea	Thailand and the Andaman Islands	Sea	Manageable 50	Monsoon winds over deep open water
45	Balearic Sea	Spain	Sea	Manageable 50	Short fetch, northerly storms and fronts
45	Baltic Sea	Northern Europe	Sea	Manageable 50	Short steep chop, no ocean swell
45	Bay of Fundy	New Brunswick and Nova Scotia	Bay	Manageable 50	Record tides, swell against the ebb at Digby Gut
45	Bay of Islands	Northland, New Zealand	Bay	Manageable 50	Open Pacific at Cape Brett, islands inside
45	Bay of Naples	Southern Italy	Bay	Manageable 50	West-facing bay, autumn and winter storms
45	Beagle Channel	Tierra del Fuego (Argentina and Chile)	Channel	Manageable 50	Narrow channel, strong westerly winds
45	Block Island Sound	Rhode Island, Connecticut and New York	Sound	Manageable 50	Open to the Atlantic, southerly fetch
45	Bocaina Strait	Canary Islands	Strait	Manageable 50	Trade-wind chop in a short, shallow strait
45	Caribbean Sea	Caribbean	Sea	Manageable 50	Trade winds, winter surges and hurricane season
45	Cebu Strait	Philippines	Strait	Manageable 50	Island channel, rougher in monsoons and typhoons
45	Chesapeake Bay	Maryland and Virginia	Bay	Manageable 50	Shallow bay, long fetch, wind against tide
45	Coral Sea	South-west Pacific	Sea	Manageable 50	Trade-wind chop behind a reef screen
45	Cozumel Channel	Mexican Caribbean	Channel	Manageable 50	Strong current, norte winds
45	Delaware Bay	New Jersey and Delaware	Bay	Manageable 50	Open bay, long fetch and strong currents
45	English Channel	North-west Europe	Strait	Manageable 50	Shallow strait, wind against tide
45	Firth of Clyde	West of Scotland	Firth	Manageable 50	Sheltered firth behind the Kintyre Peninsula
45	Flores Sea	Eastern Indonesia	Sea	Manageable 50	Fast currents in the island channels
45	Galway Bay	West of Ireland	Bay	Manageable 50	Atlantic swell entering through the Aran sounds
45	Gozo Channel	Malta	Channel	Manageable 50	Short, shallow channel between two islands
45	Gulf of California	Mexico	Gulf	Manageable 50	Long, deep gulf, brief chubasco storms
45	Gulf of Finland	Finland and Estonia	Gulf	Manageable 50	Narrow gulf, wind along its axis
45	Gulf of Honduras	Honduras, Guatemala and Belize	Gulf	Manageable 50	Trade winds on open water, storms in late summer
45	Gulf of Mexico	North America	Gulf	Manageable 50	Winter northers behind cold fronts
45	Gulf of Saint-Malo	Between Brittany, Normandy and the Channel Islands	Gulf	Manageable 50	Huge tides and island reefs in the western Channel
45	Gulf of Salerno	Amalfi Coast, Italy	Gulf	Manageable 50	Wide open Tyrrhenian mouth, winter storms
45	Gulf of Thailand	South-east Asia	Gulf	Manageable 50	Shallow gulf, monsoon wind chop
45	Ha Long Bay	Northern Vietnam	Bay	Manageable 50	Island-shielded bay, storm-season closures
45	Hauraki Gulf	New Zealand	Gulf	Manageable 50	Protected gulf, exposed to north winds
45	ʻAlalākeiki Channel	Maui, Hawaii	Channel	Manageable 50	Afternoon trade winds and strong currents
45	ʻAuʻau Channel	Maui, Hawaii	Channel	Manageable 50	Island-sheltered channel with offshore gusts
45	Inside Passage	North Pacific	Coastal waterway	Manageable 50	Island shelter, except at its open crossings
45	Ionian Sea	Western Greece and southern Italy	Sea	Manageable 50	Winter southerlies over deep open water
45	Irish Sea	British Isles	Sea	Manageable 50	Wind against strong tidal streams
45	Kattegat	Denmark and Sweden	Sea	Manageable 50	Shallow sea with tiny tides
45	Korea Strait	East Asia	Strait	Manageable 50	Monsoon chop over a shallow shelf
45	Ligurian Sea	North-west Italy and Corsica	Sea	Manageable 50	Mistral and Gulf of Genoa lows over deep water
45	Long Island Sound	New York and Connecticut	Sound	Manageable 50	Sheltered sound, long east-west fetch
45	Malta Channel	Central Mediterranean	Channel	Manageable 50	Open channel exposed to north-westerly gales
45	Mediterranean Sea	Mediterranean	Sea	Manageable 50	Mistral in the west, meltemi in the Aegean
45	Milford Sound	Fiordland, New Zealand	Fiord	Manageable 50	Sheltered fiord with an open-sea mouth
45	Mona Passage	Caribbean	Passage	Manageable 50	Tidal current forced over shallow banks
45	Monterey Bay	Central California	Bay	Manageable 50	Winter storms and swell in an open bight
45	Moreton Bay	Brisbane, Australia	Bay	Manageable 50	Shallow bay behind sand islands, wind chop
45	Nantucket Sound	Cape Cod, Massachusetts	Sound	Manageable 50	Winter gales over shoal-filled water
45	Northumberland Strait	Prince Edward Island and Nova Scotia	Strait	Manageable 50	Shallow, exposed strait, autumn depressions
45	Pamlico Sound	Outer Banks, North Carolina	Sound	Manageable 50	Shallow lagoon, short choppy sea in strong wind
45	Pearl River Estuary	Southern China	Estuary	Manageable 50	Shallow estuary, monsoon wind and typhoons
45	Pillsbury Sound	US Virgin Islands	Sound	Manageable 50	Trade-wind chop in a small sound
45	Port Phillip	Victoria, Australia	Bay	Manageable 50	Sheltered bay, turbulent tide at the Heads
45	Prince William Sound	South-central Alaska	Sound	Manageable 50	Sheltered fjords, Gulf swell at the entrance
45	Resurrection Bay	Southcentral Alaska	Bay	Manageable 50	Sheltered fjord, open Gulf of Alaska swell beyond
45	Río de la Plata	Argentina and Uruguay	Estuary	Manageable 50	Wind along the river's axis over shallow water
45	Rottnest Channel	Western Australia	Channel	Manageable 50	Open-shelf swell, summer sea breeze
45	Salish Sea	North Pacific	Marginal sea	Manageable 50	Mountain-sheltered basins, one strait open to the Pacific
45	San Francisco Bay	Northern California	Bay	Manageable 50	Funneled summer sea breeze and tidal swirls
45	San Pedro Channel	Southern California	Channel	Manageable 50	Open Pacific channel, spring peak
45	Saronic Gulf	Athens, Greece	Gulf	Manageable 50	Summer meltemi, partly sheltered by Attica
45	Sea of Åland	Sweden and the Åland Islands	Sea	Manageable 50	Deep basin joined to the open Baltic
45	Sea of Marmara	Istanbul, Turkey	Sea	Manageable 50	Small basin, wind-built waves over long fetches
45	Seto Inland Sea	Western Japan	Marginal sea	Manageable 50	Sheltered inland sea, strong tidal straits
45	Singapore Strait	South-east Asia	Strait	Manageable 50	Sheltered strait, monsoon wind chop
45	Sir Francis Drake Channel	British Virgin Islands	Channel	Manageable 50	Steady trade winds between islands
45	Skagerrak	Scandinavia	Strait	Manageable 50	North Sea swell funneled into a narrowing strait
45	St Lucia Channel	Eastern Caribbean (Martinique and Saint Lucia)	Channel	Manageable 50	Trade-wind sea in a gap between islands
45	Strait of Gibraltar	Spain and Morocco	Strait	Manageable 50	Wind funneled between two mountain ranges
45	Strait of Malacca	Malaysia and Indonesia	Strait	Manageable 50	Sheltered strait with Sumatra squalls
45	Strait of Messina	Sicily and Calabria	Strait	Manageable 50	Opposed tides drive strong currents through a 3 km gap
45	Straits of Florida	Florida and the Bahamas	Strait	Manageable 50	Gulf Stream current, trade winds, hurricane season
45	Straits of Mackinac	Northern Michigan	Strait	Manageable 50	Irregular currents and autumn gales between two lakes
45	Sydney Harbour	New South Wales, Australia	Harbour	Manageable 50	Harbour with an open ocean entrance
45	Table Bay	South Africa	Bay	Manageable 50	Open to the north-west, winter storm waves
45	The Minch	North-west Scotland	Strait	Manageable 50	Atlantic swell down an open northern door
45	The Solent	Southern England	Strait	Manageable 50	Short fetch with fast tidal streams
45	Tyrrhenian Sea	Western Italy, Sardinia and Sicily	Sea	Manageable 50	Winter mistral and libeccio over deep water
45	Verde Island Passage	Philippines	Strait	Manageable 50	Two monsoons and a typhoon season
45	Vieques Sound	Puerto Rico	Sound	Manageable 50	Steady trade winds over a long fetch, shoals in the west
45	Vineyard Sound	Cape Cod, Massachusetts	Sound	Manageable 50	Wind against tidal current at West Chop
45	Wadden Sea	Netherlands, Germany and Denmark	Intertidal sea	Manageable 50	Sheltered tidal flats, wind-driven chop
45	Whitsunday Passage	Queensland, Australia	Passage	Manageable 50	Wind across the gap to the islands
45	Zanzibar Channel	East Africa	Channel	Manageable 50	Open Indian Ocean channel, monsoon winds

128 entries. Equal ratings tie on purpose: the guides rate in four bands, and this table does not pretend to more precision than they carry.

How this table is ranked

Each crossing inherits the rating already published in its Dizzout sea guide. A guide rates a crossing in one of four bands, gentle to notorious, from three things we can actually check: the geography that shapes its waves (fetch, shelf depth, tidal flow), operator and route information, and what passengers consistently report. The bands map to fixed scores (gentle 25, manageable 50, rough 75, notorious 92), equal ratings tie, and the way to break a tie is to read the two guides.

Nothing here is a measurement of your sailing day. A notorious strait has flat afternoons and a manageable sea has ugly ones: the rating is about how often each water misbehaves, not a forecast.

The data behind this table

The full Nausea Index: every rated journey on the site in one cross category list.
The World Nausea Map: the same ratings placed where they actually are.
Motion sickness statistics: who gets motion sick, and how often, with sources.

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Questions people ask

What is the roughest sea crossing in the world?

Our guides rate 6 entries notorious, the top band: Bering Sea (Aleutian Low storms over a wide deep basin); Drake Passage (No land to stop wind, swell or current); Foveaux Strait (Roaring Forties swell over a shallow seaway); and 3 more. Equal ratings tie on purpose, and each name links to the full guide behind its rating.

Does a rough crossing always mean you will be seasick?

No. Susceptibility varies a lot between people, and even the notorious crossings have calm days. The rating tells you how often a water misbehaves, so you know how much preparing matters: pick your sailing season with care, book midships, and have a plan for the first rough hour.

When are these crossings at their worst?

Most of them peak in their local storm season, and several are dramatically calmer for months at a time. Each crossing's guide lists its rough months and its calm ones, which is often the difference between an ugly trip and an unremarkable one.

Keep going

Other cuts of the index: bumpiest road trips, biggest cruise ships, worst disney and universal rides.

Updated 2026-10-03. Ratings and figures come from the Dizzout guides linked in each row and change only when a guide changes. This page is educational and is not medical advice.