Where to Dive Each Month: Best Time to Dive by Destination

Where to dive each month: the short list

Each month below has three picks from different oceans, each tied to a season, a sea condition or an animal event you can plan around. Our destination guides go deeper on single places.

Read every window as a probability. DBCA, the agency that manages Ningaloo Marine Park, says whale sharks are most reliably seen there from March to July, and that in some years they stay into August, September and even October. Australia's Coral Coast, the regional tourism body, adds that the dates may vary from year to year. The middle of a window is the safer booking. The edges are a gamble.

Why the same dive site changes from month to month

Wind and currents, mostly. In the Maldives the monsoon reverses twice a year. The Manta Trust's Baa Atoll report describes the southwest monsoon (May-October) as the season of more rain, lower visibility and rough seas. It is also when currents hit the atolls, which rise about 2,000 m from the seafloor, and push nutrient-rich water up. That upwelling feeds the plankton the mantas come for. The Maldives Manta Conservation Programme describes the country's reef mantas as year-round residents that move across its 26 atolls with the monsoons.

So the clearest water and the biggest animals often fall in different months. Galápagos shows the same split. Between May and December, south-easterly winds bring cool water to the southern islands, and the Galapagos Conservation Trust says the sea is choppiest from June to September. January to April brings warmer currents and calmer water. Yet the whale sharks at Darwin Island pass mostly from around June to October, according to the Marine Megafauna Foundation.

Cold upwelling also drives the mola season around Nusa Penida and Nusa Lembongan. Emperor Divers puts the main season at July to October and links it to colder, nutrient-rich water reaching the reefs. In Raja Ampat, the Biodiversity Eco Resort calls June to September the wet season, with showers and slightly lower visibility from runoff. October to April is its dry season, with calmer seas and visibility that often exceeds 30 m (100 ft).

Dive or snorkel? Check before you book an animal season

Several famous seasons are surface encounters. Scuba diving is banned inside the Hanifaru Bay protected area in Baa Atoll, one of the rules that followed a 2012 government management plan, along with limits on boats and visitors. The mantas still come in numbers: on 25 August 2022, researchers identified 212 reef mantas in the bay in a single day.

Mexico's whale shark management plan for the Caribbean covers observation and swimming only, and it defines swimming as moving at the surface with mask, fins and snorkel, without dives. The 2025-2027 plan sets the season from 15 May to 17 September, and CONANP says the strongest months are July and August. At Ningaloo, DBCA and Tourism Western Australia describe the licensed whale shark tours as swims, while the marine park itself offers diving all year.

Darwin Island, Socorro and Cocos sit on the scuba side of the list. Most of the whale sharks passing Darwin are adult females longer than 10 m (33 ft), per the Marine Megafauna Foundation. At Socorro, Nautilus Liveaboards says humpback song can be heard on dives from January to April. If a trip is built around one animal, ask the operator in writing whether guests meet it on scuba or at the surface.

Liveaboard-only seasons: the month decides the trip

Some of the best windows can only be dived from a liveaboard, and the boats go only in season. Tubbataha's season runs from mid-March to mid-June, which coincides with the calmest seas and best visibility before the southwest monsoon. Socorro trips run from November to July, with a 24-hour crossing each way from Cabo San Lucas, per Nautilus Liveaboards. Cocos Island lies 555 km (300 nautical miles) from Puntarenas, about 36 hours by boat each way according to DAN's Alert Diver, and Undersea Hunter quotes 32-36 hours.

Those crossings take up two or three days of the trip, and the sea state decides how comfortable they are, so the month matters twice: for the animals and for the ride out. Several of these places also feature in our list of the world's top dive sites. A week of up to four dives a day ends with a flight home, so plan the last dive day with our flying after diving guide.

Hurricane and monsoon months to plan around

The Atlantic hurricane season runs from 1 June to 30 November. NOAA's National Hurricane Center puts the peak on 10 September, with most activity between mid-August and mid-October, so Caribbean trips in that stretch need flexible bookings and travel cover that handles cancellations. Bonaire is the usual exception. It sits at about 12°N, and Bonaire.com says it lies outside the official hurricane belt.

Monsoons play the same role in Asia and the Indian Ocean. The southwest monsoon brings rough seas and lower visibility to the Maldives, less predictable weather to the Sulu Sea around Tubbataha, and the wet season to Raja Ampat. Diving continues in most of these places, but crossings get rougher and conditions at the sites change.

Water temperature through the year

Warm-water destinations are not warm all year. SCUBA Travel gives the Red Sea an average range from 20°C (68°F) in February to 31°C (88°F) in September in the far south, and calls December to February low season because of the cooler water. On Turkey's Mediterranean coast, the state meteorological service's long-term averages run from 16.0°C (61°F) in February to 28.1°C (83°F) in August.

Surface figures flatter the deep water. Malta Dives notes that surface temperatures soar in summer while deeper water takes much longer to heat, and it suggests a drysuit from January to May for longer dives and a 3-5 mm full wetsuit from July to September. Raja Ampat, close to the equator, stays around 27-30°C (80-86°F) all year, according to the resort quoted above. Our wetsuit thickness guide turns these numbers into a suit choice.

The averages are also moving. Copernicus reports that 2024 was the Mediterranean's warmest year on record at 21.5°C, 1.2°C above average, and that the basin-wide daily average peaked at 28.7°C on 13 August 2024. MGM's own series for Turkey's coast shows the same drift, from a 21.0°C annual average in 1970-1980 to 22.3°C in 2014-2025. Use old monthly charts as a starting point and check recent readings before you pack.

Moon phase: timing within the month

Some events follow the moon, not the calendar. At Gladden Spit, snappers spawn after the April, May and June full moons, and one Placencia dive centre schedules its 2027 whale shark trips for 20-30 April, 20-30 May and 18-28 June. Great Barrier Reef corals also spawn after a full moon: inshore reefs typically in October, outer reefs in November or December, per the Great Barrier Reef Foundation.

In the Red Sea, SCUBA Travel notes that the winds are often weakest around the full moon, which helps on exposed offshore reefs. In the Maldives, the Manta Trust links lunar phases and strong winds during the southwest monsoon to stronger currents and more upwelling. Check a lunar calendar before you fix dates for any of these.

Before you book a seasonal trip: six checks

These checks pull the points above into one list you can run through with an operator before you pay a deposit.

• Season dates for this year. Mexico sets its whale shark season in a multi-year plan, and Tubbataha's season depends on the weather, so confirm the operator's actual dates.
• Scuba or snorkel. Hanifaru Bay bans scuba, and Mexico's whale shark rules allow surface swimming only.
• Moon phase. Gladden Spit and Great Barrier Reef spawning follow the full moon, so a week's shift can decide the trip.
• Temperature at depth. Surface averages hide colder water below, and upwelling seasons such as Nusa Penida's run cold on purpose.
• Crossing time and sea state. Socorro and Cocos add a day or more at sea each way, in the season's weather.
• Storm and monsoon cover. For Caribbean trips between June and November, read what your travel insurance pays if a hurricane cancels the trip.