Is the Sea of Marmara rough? What to expect on the crossing
Sometimes, mostly outside summer. The Sea of Marmara is a small inland sea, roughly 280 km by 80 km, so its waves are built by the local wind. The sea can be rough in spring, autumn and winter, and ferries to the Princes' Islands are sometimes cancelled in storms and high waves.
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Sea · Istanbul, Turkey · Reputation among passengers: mixed: commonly reported as uncomfortable in the wrong conditions.
- Low
- Moderate
- High
- Very high
Roughness summarises typical reported conditions for this crossing, not a forecast for any given sailing.
Small basin, wind-built waves over long fetches
In the Nausea Index table of the 121 sea crossings we cover, the Sea of Marmara is rated manageable, one of 81 in that band, with 40 rated higher. Full table: the roughest sea crossings, ranked.
Key facts
- The Sea of Marmara is a sea, and passenger reports place it in the moderate roughness band.
- The mechanism behind that reputation: Small basin, wind-built waves over long fetches.
- It is also known as Marmara Denizi / Marmara Sea.
Why does the Sea of Marmara get rough?
The Sea of Marmara covers 11,350 square km and is deep, 494 m on average and 1,370 m at most. A year of buoy records off the northern shore near Istanbul, in 50 m of water, found that 90 percent of the measured waves were 0.55 m or lower and only 1 percent were above 1 m, with the highest waves coming from the band between south-south-east and south-south-west, where the strong winds blow over relatively long fetches. The buoy sits about 3.3 km offshore and the study analysed only waves from southerly winds, so the open sea can be rougher. A 40-year hindcast of the whole sea finds the middle of the sea and the north-eastern shores of Marmara Island and the Kapıdağ Peninsula most affected by extreme sea conditions.
When is the Sea of Marmara roughest?
The sea can be rough in spring, autumn and winter, and the Princes' Islands are sometimes cut off when ferry services are cancelled because of storms and high waves. In winter, strong winds and the resulting ferry cancellations leave the islands almost deserted. The 40-year hindcast study also finds an increase in the number and severity of storm events in recent years.
Where to be on board
Front to back
- Bow (front)Avoid
- MidshipBest
- Stern (aft)OK
The crossing
Roughest stretch: The open water between the Istanbul shore and the islands
Midship on a low deck. Pick a seat with a view of the horizon and stay in it.
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The crossings that cross it
| Route | Typical duration | What to know |
|---|---|---|
| Kabataş to the Princes' Islands (fast ferry) | The Princes' Islands lie in the Sea of Marmara and are reached by ferry from Kabataş on the European shore. | |
| Kabataş to the Princes' Islands (regular ferry) | The slower regular ferry on the same route. |
What helps on this crossing
- Take the fast ferry if you can. Wikipedia gives a shorter time for the fast ferry than for the regular ferry (vapur), so you spend less time on the water.
- Go in summer, or check the forecast before a spring, autumn or winter trip. The sea can be rough in those seasons, and ferries are sometimes cancelled in storms and high waves.
- Keep your eyes on the islands or the horizon ahead and put your phone away. A fixed point to watch helps more than a screen.
For the full toolkit see the seasickness guide, or what to do once it has already started. For what the trials actually say about the oldest trick on that list, see the verdict on looking at the horizon. If the rocking follows you ashore afterwards, that is land sickness, which is normal, and it passes.
Frequently asked questions
Is the Sea of Marmara rough in July?
July is in the quieter part of the year. The sea can be rough in spring, autumn and winter, which leaves summer as the calm season. Check the day's forecast anyway, since a 40-year hindcast study finds storm events becoming more frequent and more severe.
Is the Sea of Marmara rough in January?
January is in the rough season. The sea can be rough in winter, strong winds lead to ferry cancellations, and the Princes' Islands become almost deserted.
How long is the ferry to the Princes' Islands?
Wikipedia's entry on the Princes' Islands gives about 25 minutes by fast ferry and 40 minutes by regular ferry from Kabataş, in its section on Kınalıada, the nearest island. Most ferries call at Kınalıada, Burgazada, Heybeliada and Büyükada in turn, so the farther islands take longer. Check the operator's timetable for your island.
How big do the waves get in the Sea of Marmara?
A year of buoy records off the northern shore found 90 percent of waves at 0.55 m or lower and only 1 percent above 1 m. The buoy sits about 3.3 km offshore and only waves from southerly winds were analysed, so the open sea can be rougher.
Other crossings
Sources & further reading
- https://en.wikipedia.org/wiki/Sea_of_Marmara
- https://en.wikipedia.org/wiki/Princes%27_Islands
- https://dergipark.org.tr/en/download/article-file/452539
- https://avesis.uludag.edu.tr/yayin/bfbae41a-f3ce-4b5e-82fa-ad236ff4da57/characterization-and-classification-of-wave-storm-events-and-wave-climate-on-the-sea-of-marmara
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.