Is the Portsmouth to Bilbao crossing rough?
In the stormy months, yes. Portsmouth to Bilbao runs about 32 to 33 hours with Brittany Ferries, two sailings a week, with two nights aboard and a long offshore middle section across the deepest part of the Bay of Biscay. Summer crossings are commonly gentle; late autumn ones can be memorable.
English Channel and Bay of Biscay · about 32 to 33 hours, two nights aboard · Reputation among passengers: has a long-standing reputation for rough passages.
- Low
- Moderate
- High
- Very high
Roughness summarises typical reported conditions on this route, not a forecast for any given sailing.
A long offshore middle over open Biscay
Key facts
- The Portsmouth to Bilbao crossing takes about 32 to 33 hours, two nights aboard, operated by Brittany Ferries.
- It crosses the English Channel and Bay of Biscay, and passenger reports place the route in the high roughness band.
- What drives the rough days: A long offshore middle over open Biscay.
- Conditions are reported roughest in January, February, November and December.
- The calmest months are usually June, July and August.
Taking the Portsmouth to Bilbao crossing? Put it on your phone before you go, so it is there when you need it. Drug-free, any headphones.Starts in your browser · works with any headphones
Stop seasickness. Get your personalized Dizzout plan. Paid subscription for full access.
On your phone? Scan to start there.
Why the Portsmouth to Bilbao crossing gets rough
Same bay, slightly different geometry to the Santander route: Bilbao sits further east along the Spanish coast, and the sailing spends a long stretch well offshore over the abyssal plain before closing the coast. Atlantic swell arrives unbroken out there, and where the route crosses the shelf edge the waves shorten and steepen. Two nights aboard means you meet whatever Biscay is doing lying down, which is the best way to meet it.
This route crosses the Bay of Biscay. For the full picture of that water, every crossing on it and what drives its reputation, see is the Bay of Biscay rough?
When it's worst, month by month
October to March is the heavy season, with the bay in the track of successive Atlantic depressions. Late May to August is usually settled. The shoulder months swing between the two on a few days' notice. The route sails all year, up to twice a week.
| Roughest water in Jan | Roughest water in Feb | Roughest water in Mar | Roughest water in Apr | Roughest water in May | Roughest water in Jun | Roughest water in Jul | Roughest water in Aug | Roughest water in Sep | Roughest water in Oct | Roughest water in Nov | Roughest water in Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Roughest | Roughest | Rough | Mixed | Mixed | Calm | Calm | Calm | Mixed | Rough | Roughest | Roughest |
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. Select a month to see every sea and ferry crossing ranked for it.
Where to be on board
Front to back
- Bow (front)Avoid
- MidshipBest
- Stern (aft)OK
The crossing: 32 to 33 hours
Roughest stretch: The offshore middle, over the deep bay and the shelf edge
Midship cabin, low deck, booked early. With two nights at sea, cabin position does more for comfort than anything you can buy on board.
Going on the Portsmouth to Bilbao crossing? Set it up first
Put it on your phone before you go
Whatever the forecast says on the day, you want the option already on your phone rather than a thing you go looking for at the rail. Dizzout is a drug-free app that plays precisely calibrated audio through any headphones you already own, wired or Bluetooth, with relief in about 90 seconds. Free to download.
Get your personalized Dizzout plan. Paid subscription for full access.
30,000+ travelers in 30+ countries · How we count
On your phone? Scan to start there.
Comparing apps first? See how the motion sickness apps compare
Not travelling yet? Remind me the day before my trip
Know someone who gets motion sick?
Send them the app that helps stop it, drug-free, in about 90 seconds, works with any headphones. Free to download.
What helps on this crossing
- Reserve a low, central cabin at booking; on a two-night crossing it is the highest-value decision.
- Watch the Biscay and FitzRoy sea areas in the shipping forecast before you travel.
- Keep meals light and frequent rather than one big restaurant sitting when the bay is up.
- Daylight hours are easier at a window or on deck with the horizon in view.
- Book flexibly in autumn if you can; with two sailings a week, moving one sailing later can dodge a depression.
Buying a tablet in the UK before you sail? UK pharmacies sell Kwells, Stugeron and Avomine for travel sickness, and their labels differ on when to take them. Kwells vs Stugeron and Stugeron vs Avomine set out the label facts side by side. Which one suits you is a question for the pharmacist.
For the full toolkit see the seasickness guide, or what to do once it has already started. Choosing between a fast catamaran and a conventional ship elsewhere too? The physics is the same everywhere: see the catamaran guide. If the rocking follows you ashore afterwards, that is land sickness, which is normal, and it passes.
Frequently asked questions
Is Portsmouth to Bilbao rougher than Portsmouth to Santander?
They cross the same bay and share the same seasons, so neither is reliably rougher. The Bilbao sailing runs a slightly more easterly line with a long offshore middle; on any given week the difference comes down to which day each ship meets the weather, not the destination port.
What is the crossing like in summer?
Frequently calm. Under the summer Azores high, gales in the Biscay forecast area become uncommon, and plenty of July and August crossings arrive with passengers wondering what the fuss was about. The bay's reputation is seasonal, not constant.
How do I make two nights aboard comfortable?
Cabin position first: midship and low. Then routine: eat lightly, spend daytime hours where you can see the horizon, and let the ship's motion be something to sleep through rather than fight. The crossing is long enough that pacing yourself matters more than any single trick.
Is this a crossing where people take seasickness tablets?
Many do, but whether you should is a question for a pharmacist or doctor who knows your situation. Worth mentioning to them: the crossing is about 33 hours with two nights at sea, and most motion sickness medicines are labelled for use before departure rather than mid-voyage.
Other ferry routes
Sources & further reading
Your next question, probably
Where on the ship should you be?
Which cabins move least, and what to do if you already booked one
If that is not your question:
Conditions described here are typical patterns drawn from published marine and operator information as of September 2026, not a forecast: any month can deliver a calm crossing or a bad one, and schedules, vessels and operators change. Route, vessel 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.