Ocean sunfish

Present in Bali waters during the Jul-Oct upwelling but far less reliable at Tulamben than at Nusa Penida. Do not plan a Tulamben trip around this.

Open year-round. Shore diving in a sheltered bay with resident operators, so there is no season closure and no fleet to reposition. Wet season (Dec-Feb) costs visibility, not access.

Best odds are roughly one sighting in three dives with an experienced guide during peak season, so budget multiple days. Crystal Bay is the most reliable site, typically at 20-30m. The Bali Ocean Sunfish Research Project cautions that the apparent seasonal peak partly tracks diver numbers rather than fish abundance, and that molas are also recorded outside the cold window.

No closure, but Dec-Mar brings rough surface conditions and frequent same-day cancellations at Manta Point and Crystal Bay. Operators keep running; the boats just turn back more often. Book buffer days in those months.

Sep-Dec with the cold water, at depth. Same upwelling mechanism as Nusa Penida but a different month window, which is worth noting for anyone assuming Indonesian mola season is a single thing.

Dec-Mar is the rainy season: visibility drops and some resorts reduce or suspend operations, though there is no formal closure. Apr-Aug is the calm high season with 30-40m+ visibility, best for photographers and first-timers. Sep-Dec is the pelagic season with stronger currents and colder water. The two 'best' windows serve different divers, which is the useful thing to know.

Associated with the cold-season upwelling. Occasional rather than expected.

Open year-round with no closure; the split is a quality trade, not an access one. Cool season (Jun-Nov) means whale sharks, big-animal density, cold water and rough seas. Warm season (Dec-May) means calmer water, better visibility, more hammerhead schooling and more comfortable diving. Liveaboard permits are capped, so availability rather than weather is the practical constraint.