Yes, you can snorkel in Hawaii in December — and the water is the least of your worries. The ocean stays around 74–79°F (23–26°C), warm enough for most people without a wetsuit, and the fish, turtles and reefs don’t take the winter off. What December changes is the map, not the water. From roughly November through April, North Pacific storms send serious swell into north- and exposed west-facing shores, so the famous summer spots on Oahu’s North Shore, Kauai’s north shore and West Maui can turn into surf breaks overnight — while south-facing and sheltered shores often stay calm. This guide is the December version of that map: where it’s calm, which summer spots to skip, the morning check that decides your day, and the winter spot list by island. For the year-round picture, start with our best time to snorkel in Hawaii guide and our best Hawaiian island for snorkeling.
The short answer
Yes — December is a good snorkeling month in Hawaii if you pick the right side of each island. The water is warm, the south shores are often at their calmest, and December brings a bonus no summer month has: humpback whales arrive, and by February you can sometimes hear them singing underwater. The catch is the north shores. December is the start of big-wave season, so do not plan a trip around Sharks Cove, Tunnels Beach or Honolua Bay and expect to get in. The rule for the whole month: snorkel south-facing and sheltered shores, go in the morning, and check the surf forecast before you drive anywhere. If you do that, December snorkeling is every bit as good as July — quieter, even, because the summer crowds are gone.
Why December changes the map, not the water
Hawaii’s official ocean-safety program splits the year into two surf seasons: summer from May through October, and winter from November through April. In winter, north-facing shores can see some of the year’s largest surf, while south shores generally see smaller waves. That single fact redraws the snorkeling map every December.
The water itself barely notices the season. December ocean temperatures typically run 74–79°F (23–26°C), and daytime air temperatures run from the mid-70s to the low 80s Fahrenheit, with mornings and evenings dropping into the mid-60s. Most snorkelers are comfortable bare-skinned or in a rash guard; a thin 1–3mm wetsuit is plenty if you chill easily or plan a long float. What does change in December is the rain. December is one of the wetter months, especially on windward (east and northeast) sides, and heavy rain can cut visibility in the water even when the surf looks fine — runoff clouds the shallows near stream mouths. A rainy morning is a reason to pick a different beach, not to cancel the day.
The practical consequence: your July spot list is not your December spot list. The summer-only North Shore pages on this site — Sharks Cove, Sunset Beach, Waimea Bay, Ehukai Beach and Three Tables on Oahu, Tunnels Beach and Ke’e Beach on Kauai, Honolua Bay on Maui — all say the same thing in their own guides: winter is the no-go season there. Treat those as places to watch surfers in December, not places to swim. The spots below are the December replacements.
The morning check that decides your day
No list outranks the morning forecast. Winter conditions can flip fast — a northwest swell can wrap around an island and change a west-side snorkel day in hours — so run this check before you load the car, and run it again from the sand before you get in.
- Check the surf forecast by shore, not by island. The National Weather Service Honolulu surf forecast breaks every island down by compass shore — north, south, east, west — with heights and direction. A “3–5 ft north” reading means nothing for a south-shore beach, and everything for a north-shore one. Look for south-shore readings under about 1–2 feet and light winds.
- Check a snorkel-specific forecast. SnorkelForecast scores each beach on wave height, wind, water temperature, tide and daylight, and Safe Beach Day rates Hawaii beaches for hazards like high surf, strong currents and jellyfish. Use one of these as your second opinion, not your only one.
- Go in the morning — before 11 a.m. if you can. Winds usually pick up later in the day, and visibility is generally best before afternoon chop builds. A calm 8 a.m. can be a choppy 2 p.m. at the same beach.
- Ask the lifeguard. Once you are standing on the sand, the lifeguard tower outranks everything on the internet. Ask before getting in, and stay out if the lifeguard says so. If there is no lifeguard, be doubly conservative.
- Look at the water for two full minutes. Whitecaps on the reef, brown runoff plumes near a stream mouth, surge washing across the reef flat, or a shorebreak you can’t time — any one of those is a reason to drive to the next beach on the list. December gives you options; use them.
If all five checks pass, get in. If any one fails, move on. That discipline is the whole difference between a great December snorkel day and a story you tell later.
Where to snorkel in Hawaii in December — by island
Oahu: the southeast corner carries winter
Oahu gives winter snorkelers the strongest southeast-side starting point in the state. Hanauma Bay is the headliner: a sheltered, lifeguarded bay with a reef you can walk into, and in December it is often calmer than the rest of the island. Plan ahead, though — nonresident visitors pay $25 (ages 13 and up) plus a small online fee, parking is $3, reservations open at 7 a.m. HST two days ahead, and the preserve is closed Mondays and Tuesdays. Check the live reservation listing before making a special trip; fees and operating rules change, and holiday-week slots go fast.
If Hanauma reservations don’t line up, work the Diamond Head end of Waikiki. Kaimana Beach, by the Waikiki Aquarium, is a quiet reef to scout from shore before committing, and the Diamond Head beach rocks below the crater are a morning-only option with a rocky entry and no lifeguard. On the west side, the Ko Olina lagoons are man-made and more protected than the open coast — still assess them on site before entering. At the north end of the island, Kuilima Cove at Turtle Bay is the one North Shore exception worth checking: the cove is reef-protected and can be calm on days when the rest of the shore is firing, but it is a check-that-morning spot, never a plan-A in December. Everything else on the North Shore — Sharks Cove, Sunset, Waimea, Ehukai, Three Tables — is for watching surfers until spring. Our North Shore Oahu snorkeling guide explains the winter no-go rule spot by spot.
One December-specific Oahu note: at Waikiki, box jellyfish have a documented arrival pattern about 8 to 12 days after a full moon. Treat that as an expected higher-risk window, not a schedule or an all-clear — check the jellyfish calendar and the lifeguard tower before getting in.
Maui: the Wailea–Makena strip is your winter home base
South Maui is where winter snorkelers should start. The run of beaches from Wailea down to Makena puts you on the south side of the island, where winter surf is often smaller — a starting point, not a guarantee. Keawakapu Beach is the long, easy-entry anchor; Ulua Beach and Makena Landing are the reefier stops along the same strip; Ahihi-Kinau at the end of the road is the lava-coast reserve for confident snorkelers on a flat morning. Kamaole Beach in Kihei rounds out the strip with lifeguards and facilities — the family pick. Our Kihei snorkeling guide covers the whole south-coast run in one place.
For a boat day, Molokini Crater is the December-proof choice: a crescent islet off Maui’s southwest coast in a protected marine conservation district, and the water inside the crater is usually the clearest you’ll find anywhere in winter. Book the earliest practical departure — currents inside the cove get stronger when afternoon winds pick up — and book early in your trip, because December is peak season and the good boats sell out.
The caution zone is West Maui. Black Rock at Kaanapali and Kapalua Bay are daily-condition checks in December, not winter anchors: a north swell can make snorkeling unsafe there, especially when high surf, shorebreak, wind or currents are running. Treat them as bonus spots you check that morning. Honolua Bay, further up the west coast, is a winter skip — it is a surf break from November to April.
Big Island: check Kona’s leeward coast first
Kona’s west coast is the Big Island’s winter bet, but don’t confuse a west-side location with automatic calm — northwest swell can still wrap down the shoreline, so check the daily forecast first. Kahalu’u Beach Park in Kailua-Kona is the practical first stop: easy to reach, easy to scout from shore, and easy to walk away from if the morning doesn’t look right. Two Step at Honaunau Bay is the step up — the entry sits beside the boat ramp, so stay clear of boat traffic and choose your entry carefully. Kamakahonu Beach, the small royal beach in front of the Kona pier, is the sheltered family option right in town. Kealakekua Bay (Captain Cook) has the richest marine life and the clearest-water days on the coast, but Ka’awaloa Cove is boat-only, conservation-district rules apply, and vessel-landing restrictions mean you go with a tour or not at all.
The Kona classic is the manta ray night snorkel. It runs year-round and December is a fine month for it — just check current availability, your operator’s schedule and cancellation terms before building the rest of the day around it, and book it early in your trip so a weather cancellation leaves room to reschedule. Our Kona snorkeling guide has the full leeward-coast list. On the Hilo side, expect more rain and rougher water in December; the Hilo snorkeling guide covers the east-side options honestly.
Kauai: start south, then check conditions
Kauai demands the most discipline in winter, because its popular north-shore spots can turn dangerous. At Tunnels and Ke’e, do not treat a winter map pin as permission to enter: winter surf and current can make north-shore snorkeling unsafe, and Ke’e is exposed to high winter surf that can generate a powerful rip current. Plan your water time on the south shore first and enjoy the north from land when winter surf is running. Our which side of Kauai is best for snorkeling guide explains the north-vs-south season split in detail.
The south side gives you the better places to check. Poipu Beach Park is one of the south shore’s lifeguarded beaches and the December anchor — on a flat day, inspect Lawai Beach from shore before deciding whether to enter, and don’t force an entry because the map says “south shore.” For families, Lydgate Beach Park on the east side has two rock-walled ponds built into the shoreline. They are more sheltered than the open coast, which can make them useful when conditions elsewhere are rough — but they are not weather-proof, so check conditions and talk to the lifeguard before getting in. Anini Beach is the north shore’s one reef-protected exception: the fringing reef keeps it calmer than Tunnels or Ke’e, but in December it is still a check-that-morning spot, not an anchor. Hideaways Beach in Princeville is a winter skip — the cliff access and exposed reef are a summer-only proposition.
December vs January vs February
Winter is not one month. The three months differ in crowds, whales and weather, and the difference matters for planning.
| Month | Water | Crowds & prices | Whales | Best for |
|---|---|---|---|---|
| December | 74–79°F (23–26°C) | Holiday peak: Christmas and New Year weeks are the busiest and priciest of winter; book tours and Hanauma reservations early | Arriving — first humpbacks of the season | Festive trips; south-shore snorkeling with whale season just starting |
| January | 74–78°F (23–26°C) | Still peak season, but the holiday crush eases after the first week | Peak numbers building; song audible underwater | The best all-round winter month: peak whales, slightly thinner crowds |
| February | 73–78°F (23–25°C) | Peak season continues; Valentine’s and Presidents’ Day weekends spike | Peak — the most whales and the best chance of hearing song underwater | Whale watching combined with snorkeling; the most reliable whale month |
The through-line: the water stays warm all three months, the south shores stay the winter bet all three months, and the north shores stay off-limits all three months. What changes is the whale season ramping up and the holiday crowds thinning after New Year. If you can choose, January is the sweet spot — peak whales without the Christmas-week crush.
What to pack for winter snorkeling
December packing is barely different from summer packing — one layer and one timing habit cover it.
- A long-sleeve rash guard. It does three jobs in December: sun protection, a little warmth on a long float, and jellyfish-sting cover at Waikiki in the post-full-moon window. It weighs nothing and lives in your day bag.
- A thin wetsuit top (1–3mm) if you chill easily. Most people don’t need one at 74–79°F, but if you plan hour-long floats or you run cold, it turns a good day into a comfortable one. Rental shops stock them — see our snorkel gear rental guide for what rentals cost and where to get them.
- Mineral sunscreen, reef-safe. Hawaii law prohibits the sale and distribution of sunscreens containing oxybenzone or octinoxate, and Maui County goes further with a mineral-only rule — non-mineral sunscreen can’t be sold, distributed or used there without a prescription. Look for non-nano zinc oxide or titanium dioxide, and check the ingredients yourself. Our reef-safe sunscreen guide explains the rules island by island.
- Your own mask and fins if you’ll snorkel three or more days. Boat trips run $85–275, and for three-plus days in the water, buying your own mask and fins for $40–60 beats the rental line every morning. Our snorkeling gear checklist covers what to bring and what to skip.
- A morning alarm. The single most useful piece of winter snorkel gear is a 7 a.m. start. Morning water is calmer, the wind is lighter, the light is better for seeing reef color, and the Hanauma reservation slots open at 7 a.m. HST two days ahead.
Winter snorkeling safety: five rules
December rewards the careful and punishes the casual. These five rules are the whole safety section, and they are all specific to winter.
- Never snorkel a north- or exposed west-facing beach in December without checking the surf forecast that morning. Summer habits will get you in trouble — the beach that was flat in July can be a surf break in December. If you are new to snorkeling, start with our beginners guide and our how to snorkel in Hawaii before your first winter swim.
- Never snorkel alone, and never enter water you haven’t watched for two minutes. Winter swell arrives in sets — a flat minute can be followed by a big one. Watch, then decide.
- Stay out after heavy rain. Rain itself doesn’t stop a snorkel, but the runoff after it does: brown water near stream mouths means poor visibility and bacteria, and flash-flood runoff can carry debris. Give it a day, or drive to a beach away from stream mouths.
- Keep your distance from wildlife — 10 feet from turtles, 50 feet from monk seals, 100 yards from whales. Winter is whale season, and a snorkel boat can offer whale sightings on the ride out, but people and vessels must stay at least 100 yards from humpback whales. If you hear whale song underwater, enjoy it from where you are — don’t chase it.
- If the lifeguard says no, the answer is no. There is always another beach on the list. Our is snorkeling in Hawaii safe guide covers the full safety picture, including full-face masks, currents and what to do if you get into trouble.
Frequently asked questions
Is it too cold to snorkel in Hawaii in December?
No. December ocean temperatures typically run 74–79°F (23–26°C), which is comfortable for most people without a wetsuit — a thin 1–3mm wetsuit or a rash guard is enough if you chill easily. The air is mid-70s to low 80s by day. December is cold only compared to August, not compared to anywhere on the mainland.
What is the best island for snorkeling in December?
Maui and the Big Island are the most reliable December picks: Maui’s Wailea–Makena strip and Molokini are south-facing and sheltered, and the Big Island’s Kona coast is leeward and usually calm. Oahu is a close third thanks to Hanauma Bay and the southeast corner. Kauai is the trickiest — its best winter snorkeling is on the south shore around Poipu, while the famous north shore is off-limits. Our best Hawaiian island for snorkeling guide compares the islands in detail.
Can you snorkel on Oahu’s North Shore in December?
No — not safely, and not as a plan. December is big-wave season on the North Shore, and Sharks Cove, Sunset Beach, Waimea Bay, Ehukai and Three Tables are surf breaks in winter. Go to the North Shore in December to watch the surfers, and snorkel on the southeast side instead. The one exception to check is Kuilima Cove at Turtle Bay, which is reef-protected — but only if the morning forecast and the lifeguard both say yes.
Does it rain too much to snorkel in Hawaii in December?
December is one of the wetter months, especially on windward sides, but rain rarely cancels a whole day. Showers pass, and the sun comes back. What matters is heavy rain: it cuts visibility through runoff, especially near stream mouths. If it poured overnight, pick a beach away from streams, or wait a day. A light morning shower with a calm forecast is still a snorkel day.
Can you see whales while snorkeling in Hawaii in December?
Yes — December is the start of humpback season, which runs roughly December through March and peaks in January and February. You may hear whale song underwater as early as February, and snorkel boats often spot whales on the ride out. Stay at least 100 yards from any whale, and don’t chase them — the song comes to you.
Do I need a wetsuit to snorkel in Hawaii in December?
Most people don’t. The water is 74–79°F, and a rash guard is enough for a typical 45-minute swim. Bring or rent a thin 1–3mm wetsuit if you chill easily, plan long floats, or are snorkeling with kids who cool down faster. Either way, pack the rash guard — it doubles as sun and jellyfish protection.
December is the month Hawaii snorkeling gets honest: the water stays warm, the whales arrive, the crowds thin after New Year — and the ocean tells you exactly which beaches it wants you on. Follow the sheltered shores, go in the morning, and check before you get in. Start with the best time to snorkel in Hawaii for the year-round calendar, the Oahu, Maui, Big Island and Kauai hubs for the full spot lists, and the Hawaii snorkeling tours guide if you want a boat day in the mix. The winter map is smaller than the summer map — but everything on it is worth the swim.