Is the Flores Sea rough? What to expect on the crossing
Moderately, and mostly in the channels. In wave reanalysis data (ERA5) the mean daily maximum wave height north of Komodo is about 0.9 m in January and about 0.4 m in November, but the channels between the islands, such as the Sape Strait, are known for rough seas and strong currents.
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Sea · Eastern Indonesia · 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.
Fast currents in the island channels
In the Nausea Index table of the 121 sea crossings we cover, the Flores Sea is rated manageable, one of 81 in that band, with 40 rated higher. Full table: the roughest sea crossings, ranked.
Key facts
- The Flores Sea is a sea, and passenger reports place it in the moderate roughness band.
- The mechanism behind that reputation: Fast currents in the island channels.
- Conditions are reported roughest in February.
- The calmest months are usually April, May, September, October and November.
- It is also known as Laut Flores.
Why does the Flores Sea get rough?
Wikipedia gives the Flores Sea a depth of 5,140 m, and it lies between Sulawesi to the north and the islands of Flores and Sumbawa to the south. Monsoons usually blow from the south and east in June through September and from the northwest in December through March. Wikipedia's Indonesian climate article says typhoons and large-scale storms pose little hazard to mariners in Indonesian waters and that the major danger comes from swift currents in channels, such as the Lombok and Sape straits. The Sape Strait, between Sumbawa and Komodo, is known for rough seas, shoals and strong currents.
When is the Flores Sea roughest?
Wave reanalysis data (ERA5) for 2000 to 2024 ranks January and February as the roughest months in the open sea north of Komodo and Sumbawa, with a second peak in July. November and April are the calmest. The peaks sit inside the two monsoons, which Wikipedia dates as December through March from the northwest and June through September from the south and east.
| 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Rough | Roughest | Mixed | Calm | Calm | Mixed | Rough | Mixed | Calm | Calm | Calm | 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. 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: 4 days, 3 nights
Roughest stretch: The overnight sail to Saleh Bay and the channels around Komodo
Take a cabin low in the boat and near the middle if you can. Wanua offers a private cabin for two and a mattress on a shared deck.
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The crossings that cross it
| Route | Typical duration | What to know |
|---|---|---|
| Lombok to Labuan Bajo via Komodo | 4 days, 3 nights | Wanua Adventure boat trip. It departs Saturday, Sunday, Tuesday, Wednesday and Friday, and the first night is spent sailing to Saleh Bay. |
| Labuan Bajo to Lombok via Komodo | 4 days, 3 nights | Wanua Adventure boat trip. It departs at 07:30 on Sunday, Tuesday, Wednesday, Thursday and Saturday, and one overnight leg to Moyo Island takes 14 to 17 hours. |
What helps on this crossing
- Ask for the cabin class. Wanua lists a private cabin for two against a mattress on a shared deck, and the Lombok to Labuan Bajo trip sails through the first night.
- Expect the bumpiest water in the channels between islands, where currents run hard. Keep your eyes on the horizon there, which is the best-supported free fix for motion sickness.
- Check the BMKG maritime site before you fix dates. It publishes a weekly wave outlook and a 7 day wave forecast, and January and February are the roughest months in the data.
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 Flores Sea rough in January?
January is one of the two roughest months. In wave reanalysis data (ERA5) for 2000 to 2024, the mean daily maximum wave height north of Komodo is about 0.9 m in January, against about 0.4 m in November. It sits inside the northwest monsoon, which Wikipedia places in December through March.
Is the Flores Sea rough in July?
July is a second, smaller peak. The data shows a mean daily maximum wave height of about 0.7 m north of Komodo, and 37% of July days are above the annual 75th percentile there. It falls inside the south and east monsoon, which Wikipedia places in June through September.
Is the Flores Sea rough in November?
November is the calmest month in the data, at about 0.4 m mean daily maximum wave height north of Komodo, with 3% of days above the annual 75th percentile. April is nearly as calm, at about 0.4 m with 6% of days above.
Why is the Sape Strait rough?
Wikipedia says the Sape Strait is known for rough seas, shoals and strong currents. Its climate article for Indonesia names swift currents in channels such as the Lombok and Sape straits as the major danger to mariners, ahead of storms.
Other crossings
Sources & further reading
- https://en.wikipedia.org/wiki/Flores_Sea
- https://en.wikipedia.org/wiki/Sape_Strait
- https://en.wikipedia.org/wiki/Climate_of_Indonesia
- https://wanuaadventure.com/4days-3nights-lombok-to-flores/
- https://wanuaadventure.com/4days-3nights-flores-to-lombok-island/
- https://maritim.bmkg.go.id/
- https://open-meteo.com/en/docs/marine-weather-api
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.