10 Things That (No One Ever Told You) Can Kill You in Costa Rica

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Our decision to go to Costa Rica was on a whim, and apart from buying durable hiking shoes, we were not prepared.

As we arrived we heard many of the locals allude to the dangers of Costa Rica, I mean, it is mainly rainforest after all, but yet, no one actually ever specified what we should be wary of.

And, no, it’s not sloths.

When we checked in to our room at Blue Osa Yoga Retreat & Spa, all of the guests were given flashlights. We were instructed that any time we go anywhere after dark, flashlights were a must for our safety as wild creatures could be lurking around. We were surrounded by jungle after all.

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Osa Peninsula - Aug 2014

Again, no mention as to what these creatures might be.

Johnny and I actually weren’t given flashlights because our room was attached to the brightly lit lobby, meaning we didn’t need to venture through the dark. We were told we wouldn’t be needing them.

We wouldn’t be needing them…?

Of course, we should have had a flashlight, because we did need them!

One night after dinner I decided to put my camera away before hanging out with others back in the lobby. Running upstairs I fumbled around for the light switch in our room. It was already dark outside, which meant there wasn’t enough light coming in through the windows to actually see.

Slapping my hand around on the wall like an idiot, I finally managed to hit the switch.

And there, about two inches from where I had just slapped my hand on the wall was a scorpion. Yes, a scorpion. Just chillin’ in our bedroom.

Definitely could have used that flashlight.

Then next day as we went kayaking through the mangroves, our guide briefly slipped in a joke about being careful for crocodiles before quickly moving on to a new topic. Except– he wasn’t kidding as we later maneuvered our kayaks right past some.

Again, pretty sure someone should have warned us about the crocodiles?

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Osa Peninsula - Aug 2014

I guess most local Costa Ricans don’t even think about the possible dangers anymore because they’re so used to it and actually know what to look out for.

Our same guide then proceeded to have us go swimming, promising there’d be no more crocodile encounters. What he did fail to mention however, were the jellyfish.

As members of our group ran out of the water, legs swollen and in pain, they asked the guide what was happening. Was it sand fleas? A weird allergic reaction? Our guide simply laughed and said “Oh! It must be the jellyfish that are always here… they’re micro jellyfish, so you can’t see them.”


Again, why did no one warn us of this??

This seemed to be a reoccurring theme throughout our trip, until finally, someone (an American expat mind you) had the courtesy to tell us what we should be careful of.




Osa Peninsula - Aug 2014

Most spiders are nothing to fear, but there are a few venomous varieties in Costa Rica, including the Brazilian Wandering Spider– said to be the most poisonous in the world.

The spiders you do have to worry about typically live deep within the jungle, but this means you need to take the proper precautions for dress and always wear closed-toed hiking boots. Lucky for you most spiders don’t attack unless provoked, so if you do happen to encounter a scary looking spider, just try leaving it alone and walk in the opposite direction.


Well, I didn’t know jellyfish were an issue in Costa Rica but I do now. I did, however, know that those who head to Costa Rica for surfing need to be wary of bull sharks.

These sharks are seemingly friendly and harmless, but they can turn aggressive very quickly.


While millipedes are mostly harmless, you do need to watch out for centipedes.

A bite from these long little guys can also send you to the hospital. The venom of a centipede is annoying and causes a lot of pain; however, it’s actually an allergic reaction that causes death in most humans.


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Osa Peninsula - Aug 2014

Now scorpions won’t exactly kill you, but their sting is painful and can send you to the hospital.

There are 14 different species of scorpions living in Costa Rica and they all look different. Ranging in colors of red, yellow and brown, they also come in all different sizes.

If you’re stung by a scorpion, wash the infected area with soap and water. Usually pain will subside within an hour, but if it doesn’t and the swelling hasn’t gone down, you’ll need to consult a doctor.


Mosquitoes in Costa Rica are horrible and they’re there all year round! There’s not much you can do to prevent getting bit from these suckers. Not even high percentages of Deet seemed to deter them.

Dengue Fever and Malaria are common problems here, so make sure to still use repellent every few hours or talk to your doctor about taking medicine to help prevent this.


You’ll see colorful frogs all over Costa Rica. While I find them cute and associate them with the fun mascot of Rainforest Cafe, these little guys are actually quite harmful.

Some species of frogs won’t kill you, but they will make you hallucinate. Others, like the various species of tiny poison dart frogs, are highly deadly to humans. So don’t let their small size fool you!


Osa Peninsula - Aug 2014

Apparently Costa Rica has more crocodile deaths and attacks than anywhere else in the Western Hemisphere.

Because Costa Rica is rapidly expanding, crocodiles keep having to move into new territories and can be found in even the unlikeliest of places. We saw a crocodile every day of our trip, and they were usually just inches from the road.


If you’re afraid of snakes, you may want to reconsider a trip to Costa Rica. You can find 140 species of snake here and 22 of those are incredibly deadly.

The main ones you need to watch our for are the fer-de-lance, coral snakes, eyelash pit vipers and bushmasters.

Be on the lookout for really colorful snakes, although if you spot any snake be sure to alert your guide right away so he can assess the situation and take care of it if need be. Snakes are the main reason most guides will carry machetes on them. 


Unless the only jungle you’re visiting is the urban jungle of Costa Rica, I’m pretty sure you and anyone who visits will see ants on their trip. At almost any given time we could look down and see a ridiculously long trail of gigantic ants carrying leaves across the jungle. It was pretty cool to say the least, but don’t get in the ants’ way or else they will bite you.

Watch out for leaf-cutter ants, fire ants, and especially bullet ants. If you don’t know what bullet ants are, their bite is known to make people suffer for over 24 hours in pain described as worse than being shot– hence giving them their name.


Osa Peninsula - Aug 2014

The only cat I ever encountered in Costa Rica was this little sweetie at Blue Osa

Costa Rica is home to jaguars, cougars, pumas and more. While an attack from any of these cute cats could easily kill a human, I saved them for last because, let’s face it, it’s just not very likely.

We tried hard to even see one of these creatures in the wild, but during our week-long stay it just didn’t happen. Even if you do get lucky enough to encounter a big cat, there’s a good chance that it’ll run off rather than attack, especially if you stand still and don’t provoke it.


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56 thoughts on “10 Things That (No One Ever Told You) Can Kill You in Costa Rica

  1. Avatar

    Oh my gosh. What kind of spiders are present in the jungle? Are they the poisonous kind? One should really be careful when traveling no matter where they go. Safety should always come first.

    • Beth Leung
      Beth Leung says:

      Some are poisonous, but most of them aren’t. Just avoid any giant looking spiders and you’ll be fine 😉

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    KATHY says:

    This is very good to know. I’ve always wanted to visit Costa Rica, so I’m glad I read this post. I’m afraid of anything that seems scary and could harm you.

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    Yikes! I guess I’ll stick with my dream of visiting Ireland someday… haha That photo of the scorpion gave me goosebumps, I hate those things!

    Yes, pack a flashlight whenever traveling….

  4. Avatar

    Thanks for sharing. I never knew so many things can kill you in Costa Rica. This will be super handy to know for those that are planning to go.

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    My sister went to Costa Rica a few years ago and was warned about most of these things when she went. It’s scary.

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    O my GOD I HATE SPIDERS and scorpions. I thought you would do a thermal cam,also first time talking to ya, HI

  7. Avatar

    This list was really good! Even though these animals can harm you, the idea of seeing some of them (like a jaguar, wow!) is exciting for a city girl like me.

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    I cannot believe that your guide let you into water with mico jelly fish. You would think that he would know better then to let you in.

  9. Avatar

    Yikes – and yet I would still love to visit Costa Rica – one day. I’d be afraid of the snakes though, those would really scare me. Other than that I’d be fine I guess…

  10. Avatar
    JENNA says:

    Lol! Sorry to laugh, but this really cracked me up! I would totally be worried about encountering most of these (I hate any kind of creepy crawly), but I love how everyone just warned you generally and didn’t specify what to watch out for! Definitely not showing this to my husband-the snake portion would be enough to scare him from Costa Rica for sure-I think ignorance would be bliss for him, lol!

  11. Avatar
    KRYSTA says:

    I hope you had a great time aside from your new perspective of the dangers in Costa Rica. As an American that has been living and raising my family in the Caribbean of Costa Rica for 3.5 years, I can hopefully relieve your fears of these dangers. At 8.5 months pregnant I was stung by a Scorpion while doing laundry, I have never come across a live snake, though I’m sure I will now tomorrow, and the sharks, crocs and big cats have NEVER been an issue. Though these are all true things, the 2 bouts of Dengue I’ve had and the Bullet Ant bites are more to be feared than anything else. Don’t let this stop you from coming back, we have a lot to offer here, especially on the South Side. Hell, if you make it back to CR, I’ll buy you a beer at my bar, The Lazy Mon (www.thelazymon.com) just for giving it another go! Hopefully see you soon!

  12. Avatar

    Oh man… I would never, ever consider going somewhere like this. I am just not that wild and really love creepy crawlies only on TV. If I found a scorpion in my room, I’d be running out of the hotel faster than the ladies running out of the water post-jellyfish attack 😛

  13. Avatar

    Ha! I totally thought you were going to say that a sloth could kill you. Sand fleas and jellyfish give me the shivers. I read up on sand fleas before – YUCK! I had no clue that centipedes had venom. Bullet ants!!!! OMGoodness, I could not imagine being bite by one of those, and I think I saw what a leaf cutter ant looks like online, and I can see why their bite would hurt.

  14. Avatar

    Oh wow, that is pretty scarry. I never thought about traveling to Costa Rica before but now I think that the snakes may be a deal breaker if I ever decided to.

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    HILLESHA says:

    There are so many dangers that I will be paranoid the whole time if I ever decided to visit there. I almost lost my right hand over a decade ago because of a brown recluse, so I would hate to accidentally bump into the Brazilian Wandering Spider – eek! Scorpions creep me out, too.

  16. Avatar

    Wow! this was such an interesting read! I learned a lot from this and even though those are some freaky creatures I’d still love to visit!

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    I would love to visit Costa Rica, in my own little bubble lol. Oh my goodness I didn’t realize how many different dangers there were, sounds like the warnings you get for visiting Australia!

  18. Avatar
    ROSEY says:

    We used to have scorpions in Florida. I was always a bit apprehensive about them. We didn’t have crocs there, but the alligators would kill someone annually. I was always amazed at how many people got in the water anyway.

  19. Avatar

    Omg I loved how cats were everywhere when I was in Costa Rica!!! We had a “pet cat” for the week. It followed us around and cuddled poolside…. I guess it’s a very common thing there

  20. Avatar
    MEG JERRARD says:

    Haha great post Beth! And so true on scorpions! I was volunteering in CR for a few months and one morning our leader started yelling horrendously – a scoripon had been inside his shoe as he had left them outside his door that evening. Note to self – always be aware of your shoes!

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    KORI says:

    I absolutely loathe jelly fish and all of their relations. So that would be one reason I wouldn’t want to visit Costa Rica.

  22. Avatar

    Oh wow! Your post is really good in sharing that info…particularly because my family and I are interested to go. Gotta watch out for those things…except for a cat that you saw in Blue Osa. So cute!

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    Mathew Bartlett says:

    Don’t let wildlife scare you off; at least they don’t have bears.
    I travel A LOT and I feel safer with the wildlife that than any big city with people. I’m in Costa Rica right now.
    Yesterday I wrestled a caiman (actually it just bumped me and swam away), and I saw a yellow viper, a Brazilian wandering spider, and a huge black snake that we didn’t get to identify all within like 5 minutes of each other.
    For all those there are plenty of cute sloths and monkeys to see too.

  24. Avatar
    jerry says:

    what are the odds of a wandering spider or a scorpion coming into your home down there, im flying down there the end of february to look for a home to buy

  25. Avatar
    Mauricio says:

    Things that happen when you don’t finish your homework and you just do copy/paste from Australian article. 🤦‍♂️🤦‍♂️🤦‍♂️.
    Could you give us the facts now?? So ridiculous…

  26. Avatar
    Barb Kerns says:

    Neem deters Everything that flies,slithers,flies or crawls!-Best natural repellent on 🌎 & very inexpensive.

  27. Avatar
    Alexander m. Gamboa says:

    I’m from costa rica. The only two animals i don’t would joke around are the crocodiles and the snake ver de lance, we call it tercipelo. All the rest, chill out. You won’t even see them.. if you will you lucky

  28. Avatar
    Sydney Buffet says:

    I am going on my 4th CR trip in Sept. I have a terrible fear of spiders, but, I saw wanderers, wolf and death’s head. We respected each other. Go! Do not be afraid, nothing comes rushing at you. It’s an awesome place & a trip you will never forget. Just don’t expect USA. The people are wonderful, coffee amazing, sights magical. Leaf-cutters don’t attack without provocation. See the small zoo at La Paz Waterfall for jaguars. Great museums in San Jose. Enjoy Pura Vida!

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