Swell Window helps Bali and Indonesia fast-boat travelers read marine model conditions before they book or head to the harbour. Pick a route, see wave-height bands for the next three daylight days, scrub hour by hour, and compare the lowest-energy model window with the next 24-hour peak. Each route links to the operator and official BMKG marine forecast so you can confirm locally before travel. Built for common island corridors such as Sanur to Nusa Penida, Sanur to Nusa Lembongan, Padangbai to the Gili islands, Amed to Gili Trawangan, and Serangan routes. Swell Window shows forecast wave conditions only. Operators and harbour authorities make the real-time call.