Sea conditions in the Lombok Strait swing dramatically across the year. The same crossing that takes 90 minutes in calm August can be cancelled outright in February. Here is what to expect month by month.
Dry season — May through October
Trade winds blow from the southeast, the strait is generally calm in the morning, and afternoon swell rarely exceeds 1.2m. This is the booking sweet spot.
- July–August: peak season; book operators 2 weeks ahead. Sea conditions are reliably calm, with morning crossings almost glassy.
- May–June, September: shoulder months with the same calm seas but lower fares and less crowded boats.
Wet season — November through March
Northwest monsoon brings swell, lightning storms, and weather-related cancellations. Some operators suspend service for days at a stretch.
- December–February: highest cancellation risk. Always travel with at least one buffer day before any onward flight.
- November, March: transitional months. Calm days exist but are unpredictable.
April — the wildcard
April starts the dry season but residual swell from March often lingers. Bookings are cheap, but check the 7-day sea forecast before committing.
How to read the conditions
Wave height in meters is the single number that matters. A simple rule of thumb:
- < 0.6m — calm. Any boat class is comfortable.
- 0.6–1.2m — light chop. Catamarans are noticeably smoother.
- 1.2–1.8m — choppy. Avoid open speedboats if you're seasick-prone.
- > 1.8m — rough. Many operators delay; some cancel.
Booking strategy
If your dates are firm, pick the earliest morning departure — winds build during the day, so morning swell is almost always lower than afternoon. If your dates are flexible, watch the forecast for a day with sustained <1m waves and book that slot.