Sea conditions and seasickness by month

Fast boats from Bali cross two different stretches of sea. The Badung Strait, between Bali and Nusa Penida and Lembongan, is short: 35–45 minutes. The Lombok Strait, between Bali and the Gilis, is deeper and more exposed, with crossings of 1.5–3.5 hours. How the sea feels depends on the month, the time of day and where you sit.

What are the seas like each month?

This is general guidance from typical seasonal patterns, not a forecast. Any day can be calm or rough.

July and August bring the biggest swells from the south, which is also the busiest travel season. The wet season, roughly November to March, brings wind and short squalls, which can make the Lombok Strait choppy in the afternoon.

Does rain mean a rough crossing?

Not necessarily. What matters at sea is wind and swell, not rain. A grey, drizzly morning can be flat calm, and a sunny afternoon can bring a choppy crossing when the trade wind picks up. Swell is often generated far to the south, so it can arrive on a day that looks perfect from the beach in Sanur.

If you want to check before you go, look at a marine forecast for wave height and wind speed rather than a rain forecast. If it shows a big swell, choose a morning boat and a seat at the back of the lower deck.

Are morning boats calmer?

Usually, yes. Wind tends to pick up after midday, so morning crossings are often smoother. If you get seasick, take the earliest boat that suits you, especially to the Gilis.

How do I avoid feeling seasick?

• Take seasickness tablets 30–60 minutes before departure. Pharmacies in Bali sell them.
• Sit in the middle or rear of the lower deck, where the boat moves least.
• Look at the horizon, not your phone.
• Skip a heavy or greasy meal before you sail, but don't travel on an empty stomach.
• Get fresh air if you can, and keep a bag within reach just in case.
• Ginger sweets help some people.

Who decides whether boats sail?

The harbour master (Syahbandar) monitors the weather and suspends crossings when the sea is unsafe. When that happens, no operator sails, whatever the booking site says. Operators can also cancel a single departure for technical reasons.

What happens if my boat is cancelled?

If the harbour master or the operator cancels your sailing, we move you to the next available departure for free or refund you in full, whichever you prefer. We message you on WhatsApp as soon as we know. See the cancellation policy.

If you have a flight to catch, leave a buffer. We suggest travelling back to Bali the day before an international flight, especially in July and August and when crossing from the Gilis.

Are there days with no boats at all?

Yes. On Nyepi, the Balinese Day of Silence, usually in March, all Bali harbours close for 24 hours and no boats run. Other closures are announced at short notice. Days without boats are greyed out in our date picker, with the reason.

Is it safe?

We ask every operator we work with for life jackets in adult and child sizes and a radio on board; check the safety equipment listed on each boat. Listen to the crew briefing, put your life jacket on when asked, and keep the aisles clear of bags.

Which route is best if I'm worried?

The Sanur to Nusa Lembongan and Nusa Penida crossings are the shortest, at 35–45 minutes. For the Gilis, Padang Bai has the shortest crossing (about 1.5 hours), and the larger boats, such as Eka Jaya's 150-seat ferry and BlueWater Express's air-conditioned boats, move less in a swell than small speedboats. Our Gili harbour guide compares the options.