The diving season for Cocos island is year round although the conditions do vary depending on the time of year. The best time to go diving in Cocos island for wildlife is June to December, the wet season when the plankton blooms bring the schooling hammerheads and mantas. The nutrient rich water from the currents are a big draw from all kinds of pelagic life including whale sharks and mantas. The visibility is quite a bit lower than the dry season but fortunately the temperature doesn’t drop by much more than 11°F (2-3 °C). The surface conditions are also rougher and the currents are stronger at this time. The dry season, between December and May has much better water conditions with less waves and better visibility, up to 100 ft. (30 m). Less experienced divers might prefer this period and it is worth noting that the crossing to Cocos will be much easier when the sea conditions are calmer.