🔎 TL;DR
- The Sea of Cortez is colder than people expect. Water can drop to 21 °C in Jan–Feb. A 3 mm shorty Dec–Apr is the comfort line for most adults. NOAA SST data backs this.
- Currents are usually mild but Pelican Rock and the Land's End channel can pick up, especially with afternoon thermal wind. Always start the dive into the current.
- Sea-lion etiquette is non-negotiable: stay still, don't approach pups, give bulls (300+ kg with teeth) the bull's territory, never touch.
- Reef-safe sunscreen mandatory inside CONANP-protected zones (Cabo San Lucas Marine Park). Oxybenzone and octinoxate restricted.
- Lifejacket for all kids under 12, regardless of swim ability. Ear care + dehydration + sunburn cause more problems than animals do.
The temperature problem nobody tells you about
If you're arriving from a Caribbean trip — or if your snorkel reference is anywhere in the warm Atlantic — Los Cabos will surprise you in winter. The Sea of Cortez is part of the eastern Pacific, fed by the cold California Current and by canyon upwellings off the cape. Sea-surface temperature data published by NOAA's Ocean Service shows the southern Gulf of California ranges from about 21–22 °C in January–February up to 28–29 °C in August–September. That's a 7 °C swing across the year, far wider than the Caribbean (which sits 26–30 °C year-round).
The implication for snorkelers is direct: you can get cold fast in Cabo if you arrive expecting Caribbean conditions and pack accordingly. We have seen hundreds of guests in 30 minutes go from "this is great" to "I'm shivering and need to get out" because they were in a rash guard and board shorts in 22 °C water.
The fix is one piece of gear: a wetsuit. The decision tree below is what we actually recommend to clients.
| Month | Water temp | Adult comfort gear | Kid comfort gear | Notes |
|---|---|---|---|---|
| Jan | 21–22 °C | 3 mm full or 3 mm shorty + rashguard | 2 mm full + rashguard | Coldest month. Hood optional. |
| Feb | 21–22 °C | 3 mm shorty minimum | 2 mm full | Often best viz of the year. |
| Mar | 21–23 °C | 3 mm shorty | 2 mm shorty | Water starts to warm. |
| Apr | 22–24 °C | 2–3 mm shorty | 2 mm shorty | Mobula season starts. |
| May | 23–25 °C | Rashguard + board shorts (sensitive: 2 mm shorty) | 2 mm shorty | Marginal — depends on the person. |
| Jun | 25–27 °C | Rashguard + shorts | Rashguard + shorts | Pleasant. |
| Jul | 26–28 °C | Rashguard + shorts | Rashguard + shorts | Warm. |
| Aug | 27–29 °C | Rashguard for sun | Rashguard for sun | Warmest month. |
| Sep | 27–29 °C | Rashguard for sun | Rashguard for sun | Hurricane season — watch forecast. |
| Oct | 26–28 °C | Rashguard + shorts | Rashguard + shorts | Best overall month. |
| Nov | 24–26 °C | Rashguard or 2 mm shorty | 2 mm shorty | Water cooling. |
| Dec | 22–24 °C | 3 mm shorty | 2 mm full | Whale + whale shark season. |
Wetsuit rentals are easy in Cabo. Médano Beach kiosks and most dive shops rent shorty 3 mm for $15–20 USD/day, full 3 mm for $20–25 USD/day, and kids' sizes are stocked at the bigger operators. If you don't want to rent, a packable 2 mm shorty from any dive shop online ($60–120) is a one-time purchase that pays itself off in a single trip.
Currents — where they matter, and how to read them
The good news: most Cabo snorkel sites have mild current most of the time. Chileno Bay, Santa María, Lover's Beach — these are all sheltered geometries where the boat-anchored corner of the bay is essentially flat water. The problem zones are two:
Pelican Rock channel
The channel between Pelican Rock and Lover's Beach is a narrow gap where current accelerates when the offshore breeze blows or when tide changes. The rule of thumb: always swim against the current at the start of the dive, so the easier return is downstream. A reputable operator briefs this and positions the boat accordingly. If you feel the current pulling you faster than you can swim, signal the boat and float — the captain repositions to pick you up.
Land's End thermal wind
The afternoon thermal wind off the Sierra de la Laguna mountains starts around 11 am–noon most days, building through 2–4 pm. This shifts surface water and can create a moderate offshore drift on the Land's End side. The fix is timing: the calmest water of the day at Pelican Rock + Arch is before 10 am. Most experienced operators schedule the cape sites first thing in the morning.
NOAA's National Weather Service marine forecast publishes daily wind/swell predictions for Cabo San Lucas; operators check this every morning before deciding the day's run order.
Three rules for currents at any site
- Stay with your buddy and the group. Currents separate people fast.
- If you tire, float on your back and signal. Don't fight a current; conserve energy and wave to the boat.
- Lifejackets help even strong swimmers in current. No shame in wearing one on a current-prone site.
Snorkel with operators who brief currents properly. Book Los Cabos snorkeling →
Sea lion etiquette — the rules that make the encounter work
The California sea lion (Zalophus californianus) colony at Land's End is the wow moment of most Cabo snorkel trips. It also has the highest potential for guest-to-animal misbehaviour, and the sea-lion population there has the bites to prove that some guests don't follow the rules. Pinniped behaviour data and population stock assessments are published by NOAA Fisheries; population status is tracked by the IUCN Red List (currently Least Concern but population-monitored).
The four rules
- Stay calm and still. Sea lions are curious by nature. If you float passively, the juveniles will come to you. If you chase them, they ignore you.
- Do not touch, ever. Adult bulls weigh 300+ kg and have a full canine dentition. The colony tolerates respectful divers; physical contact provokes defensive bites. Pups look cuddly but their mothers will defend them.
- Give the bull's territory a wide berth. The dominant bull patrols the edge of the colony, usually marked by bigger size and a more aggressive posture. A guide who knows the site keeps the group on the female + juvenile side; you should follow the guide's positioning.
- No flash photography, no feeding, no loud noises. All three are CONANP marine park rules and all three trigger defensive behaviour from the colony.
Pupping season — extra caution
From June through August, sea lion mothers give birth to pups on the rocks. Mothers are protective; bull territoriality is up. The encounters are still excellent — pups are the most playful animals once they enter the water — but the operator brief becomes longer and stricter, and group sizes get smaller. Trust your guide if they tell you to back off; they're reading body language you might not see.
What a sea lion encounter actually feels like
If you do the rules right, here's what happens: you slip into the water about 20 m from the colony perimeter. You float face-down, breathing slowly through the snorkel, not kicking. After 60–90 seconds a juvenile (maybe two) approaches from below or from the side. They spiral, pirouette, blow bubbles, come within 30 cm of your mask. They will sometimes "mock-bite" your fin or hover next to your face. After two or three minutes they move on and another juvenile takes their place. If you chase, they leave. If you stay still, they keep coming.
Reef-safe sunscreen — the actual chemistry
This isn't a marketing pitch. Oxybenzone and octinoxate, the two most common UV-filter chemicals in conventional sunscreens, are documented contributors to coral bleaching at concentrations as low as parts per trillion. The NOAA Ocean Service and multiple peer-reviewed studies have established the link. Mexico's CONANP restricts both chemicals inside protected marine areas — including the Cabo San Lucas Marine Park where all your snorkel sites are.
What to buy
- Mineral sunscreen with zinc oxide or non-nano titanium dioxide as the active ingredient. "Non-nano" matters — sub-100-nanometre particles can still be ingested by corals.
- Look for "reef-safe", "reef-friendly", or specifically "Hawaii-compliant" labelling.
- Avoid anything with oxybenzone, octinoxate, octocrylene, homosalate, or 4-methylbenzylidene camphor.
The practical version
You can buy reef-safe sunscreen at any pharmacy in Cabo San Lucas or San José del Cabo for $12–18 USD per bottle. Many operators sell it on the boat. The cost difference vs conventional sunscreen is real but small (maybe $5/trip), and the rangers do check at busy sites like Chileno Bay.
Other safety stuff that actually matters
Sun and dehydration
Cabo is at 23°N latitude with desert-dry air. UV index regularly hits 11+ even in winter. Drink more water than you think you need; bring a 1-litre reusable bottle and refill before the boat leaves the marina. Sunburn on the back of the legs and neck while snorkeling is the most common medical incident operators see; the rashguard fixes most of it.
Ear care
Most Cabo snorkel sites are shallow (1–8 m) so ear barotrauma is rare. Where it can happen is on free-dives. If you free-dive past 3 m, equalize early and often. After a day in the water, dry your ears (a few drops of alcohol/vinegar mix works) to prevent swimmer's ear — Cabo's bacterial load in the water is low but a wet ear canal in tropical heat is a problem regardless.
Kids in the water
- Lifejacket for all kids under 12, regardless of swim ability — Mexican maritime regulation and common sense both agree.
- Rashguard UPF 50+ for full sun protection. Kids burn faster than adults.
- Limit first snorkels to 30–45 minutes; the second session of the day can be longer once they're comfortable.
- Snorkel-vest (the type that inflates) is often more comfortable than a bulky lifejacket for kids 8+. Most operators carry both.
Boat safety
Mexican Coast Guard regulations require life jackets for every passenger on snorkel boats, a VHF radio, first-aid kit, and a registered captain license. Reputable operators meet these baselines comfortably. The dock workers / port captain do random checks on operators in Cabo San Lucas; the cheap-cattle-boat operators are the ones that get fined.
What to do if something goes wrong
Most snorkel incidents in Cabo fall into three buckets: cold-water exhaustion, current panic, and minor injuries from coral or rocks. The response in all three is the same: signal the boat, stay calm, let the captain pick you up. Never try to swim back to shore against current; never abandon your buddy in the water.
- Cold-water exhaustion: exit the water, towel off, drink something warm, change clothes. Most people recover in 15–20 minutes.
- Coral or rock scrape: clean with fresh water on the boat, antiseptic, watch for infection over next few days. Cabo's reef is not heavily inhabited by fire coral, but small abrasions can still get infected.
- Sea-lion incident (rare): exit water immediately, signal boat, do not try to engage further. Bites need professional medical attention because of bacterial load.
- Jellyfish sting (rare): rinse with seawater (not fresh water), remove tentacles with a card, apply vinegar if available. Cabo doesn't have box jellyfish but does have occasional Portuguese man-of-war — your operator will know if conditions are bringing them inshore.
For dive emergencies specifically (more common on the diving side of Cabo operations), PADI recommends DAN insurance and access to the recompression chamber in San José del Cabo. For snorkel-only emergencies the local hospitals (Amerimed, Saint Luke's) handle the standard cases.
Frequently asked questions
Do I really need a wetsuit in Cabo in winter?
Yes, almost certainly. Water temperature in Jan–Feb drops to 21–22 °C, which is below what most adults can comfortably tolerate in a rash guard for more than 20 minutes. A 3 mm shorty is the practical minimum; a 3 mm full suit is better. Kids should always have at least a 2 mm full because they lose heat faster. Wetsuit rentals at the marina are $15–25 USD/day and the operators stock kid sizes.
How dangerous are the sea lions, really?
Statistically, low risk if you follow the rules. The colony has been visited by snorkelers for decades with very few incidents. Most incidents involve guests touching, chasing, or feeding the animals — all explicitly prohibited. Bulls are 300+ kg and have full teeth, so the worst-case outcome of provoking one is serious; that's the reason for the rules, not the actual risk on a normal day. A respectful snorkeler in the company of a permitted operator is at very low risk. Pupping season (Jun–Aug) requires extra caution because of protective mothers.
What if I can't swim well?
Wear a lifejacket, snorkel only at sheltered sites (Chileno Bay is the best for weak swimmers), and tell your guide upfront. Cabo operators are used to mixed-ability groups and will keep an eye on you. Pelican Rock and the Arch are not the right first-snorkel sites for a non-swimmer; they involve deeper water and panga drop-offs. The corridor sites (Chileno, Santa María) are the safer choice.
Is reef-safe sunscreen actually enforced?
Yes, increasingly. CONANP rangers patrol the busy sites (especially Chileno Bay) and reputable operators check at the dock. The science is clear — oxybenzone and octinoxate damage coral at trace concentrations — and the enforcement has tightened year over year. Buy a reef-safe brand in advance or pick one up at any Cabo pharmacy for $12–18 USD; it's a small cost for a real impact.
When are currents strongest at Pelican Rock?
Currents at Pelican Rock and the Land's End channel are strongest when the afternoon thermal wind kicks in — typically 11 am to 4 pm, with peak in early afternoon. Reputable operators schedule cape sites in the early morning (8–10 am) precisely to avoid this. If you book a tour that promises a 1 pm Pelican Rock visit, that's usually a sign the operator isn't reading conditions well. The NOAA marine forecast for Cabo San Lucas publishes wind/swell predictions every morning.
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