When To Go · Destination Guide
Hawaii Island Big Island Usa
Year-round mantas, lava-formed reefs, and easy access to deep blue water
Updated Oct 30, 2025 • 20 sources
When To Go
Season planner for Hawaii Island (The Big Island)
Diving is year-round. Leeward Kona mornings are usually calm, with trades and sea breeze building by mid-day. Winter brings more north and west swell that can add surge to some Kona sites. Summer south swells affect South Kona bays. Humpback whales visit roughly November to April. Mantas are present year-round, with encounters linked to plankton conditions rather than strict seasons.
At A Glance Heatmap
| Activity | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
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| Topside |
Activity Drilldowns
OverallSep-Nov·Crowd:Moderate·Cost:Premium
Ideal: Typically calmer seas, warm water near 27°C to 28°C.
Plan Carefully: More trade winds and potential south swells on South Kona bays.
Check volcano status, vog forecasts, and surf outlooks.
ScubaSep-Nov·Crowd:Moderate·Cost:Premium
Ideal: Frequent calm mornings and excellent Kona visibility.
Plan Carefully: North-west swells can add surge to some sites. Whales offshore.
Mantas are yearround.
FreediveSep-May·Crowd:Light·Cost:Premium
Ideal: Frequent early glass-offs ideal for line sessions.
Book safety and coaching.
SnorkelMay-Oct·Crowd:Moderate·Cost:Premium
Ideal: Warm water near 27°C and frequent morning calm.
Plan Carefully: More wrap-around swell and winter showers. Start early and pick protected coves.
Avoid brownwater events after heavy rain.
TopsideYear-round·Crowd:Moderate·Cost:Premium
Maunakea stargazing peaks on moonless, clear nights.
Seasonal Callouts Timeline
Manta Rays
JanJanFebFebMarMarAprAprMayMayJunJunJulJulAugAugSepSepOctOctNovNovDecDecNight feeding aggregations at Garden Eel Cove and Keauhou with guided in-water protocols.
Humpback Whales
JanJanFebFebMarMarAprAprMayMayJunJunJulJulAugAugSepSepOctOctNovNovDecDecBreeding season offshore of the Kohala and Kona coasts. View from boats with required standoff distances.
Pelagic Blackwater
JanJanFebFebMarMarAprAprMayMayJunJunJulJulAugAugSepSepOctOctNovNovDecDecOpen-ocean drifts reveal larval fishes, comb jellies, and pelagic invertebrates near the surface at night.