Bugs, Mosquitoes, and Creepy Crawlies: An Honest Guide for Canadians Moving Abroad

By Taraji Abroad

If you survived a childhood of Canadian blackflies, swatted your way through every June mosquito season, and have strong opinions about the size of dock spiders in cottage country — you already have more bug experience than you think.

Moving to Mexico, Portugal, or Thailand means different insects, not necessarily worse ones. Some are bigger. Some show up in new places. A few have names you’ll google at 2 a.m. during your first week. But the honest truth is: most of this is manageable with basic habits, and after about a month, you stop thinking about it entirely.

Below: the bugs in each country — Mexico, Portugal, and Thailand — how to keep them out of your apartment, and the handful of situations where you should actually pay attention.

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Health information here is general guidance — talk to a travel health clinic before your move for advice specific to your destination and health history. See our health insurance guide for coverage options.

Mexico: Mosquitoes, Cockroaches, and the Occasional Scorpion

Your first evening on a rooftop in Puerto Vallarta, drink in hand, sun going down — and then the familiar whine of a mosquito near your ear. Some things are universal.

Mosquitoes are the main insect you’ll deal with in Mexico, particularly in tropical and coastal areas. They carry dengue in some regions, which makes repellent genuinely worth using — not just for comfort, but for health. The good news: Mexico City sits at 2,200 metres above sea level, and mosquitoes are far less common at altitude. Mérida and the Yucatán are more active, especially during rainy season (June through October). Screens on your windows make the single biggest difference. When you’re apartment hunting, check for them — it’s one of those details that separates a good rental from a frustrating one.

Cockroaches show up in tropical climates everywhere on the planet, and yes, the ones in Mexico are larger than what you’re used to in Canada. This is not a cleanliness issue — they’re an outdoor species that occasionally wanders inside, especially after rain. Sealing food, taking out trash nightly, and keeping drains covered reduces encounters significantly. Most long-term residents see one every few weeks, not every day.

Scorpions are mainly a Pacific coast reality — Puerto Vallarta, Mazatlán, and parts of Oaxaca. They’re uncommon in Mexico City and Mérida. If you’re in scorpion territory, the habits are simple: shake out shoes before putting them on, keep your bed a few inches from the wall, and don’t leave clothes on the floor overnight. Most stings are painful (think bad wasp sting) but not dangerous for healthy adults. Still worth knowing where your nearest clinic is — good health insurance covers this without question. If you’re choosing a neighbourhood, our Mexico City neighbourhoods guide notes which areas are more urban (fewer insects) versus greener and closer to parks.

Portugal: The Easy One

If insects are a major concern for you, Portugal is the most straightforward of the countries we cover by a wide margin.

Mosquitoes exist, mostly in summer months and near standing water, but Portugal doesn’t have tropical mosquito-borne diseases. They’re the same nuisance-level mosquitoes you’d get in southern Ontario during August — itchy, annoying, not dangerous. A plug-in repellent device (available at any pharmacy for a few euros) handles most indoor situations.

Flies are more noticeable in rural areas and during hot months. If you’re renting outside Lisbon or Porto — in the Algarve countryside, for instance — screens help, but many older Portuguese buildings don’t have them. Worth checking during your apartment search.

That’s essentially it. No tropical insects. No scorpions. No dengue risk. Portugal’s climate is Mediterranean, and the insect situation reflects that. If you’re coming from anywhere in Canada, the bug situation in Portugal will feel like an upgrade.

Thailand: Mosquitoes, Ants, and Your New Gecko Roommates

Thailand is tropical, and tropical means more insects. But it also means an entire ecosystem that manages them — including some allies you might not expect.

Mosquitoes are present year-round, with higher activity during rainy season (May through October). Dengue is a real consideration in parts of Thailand, though central Chiang Mai and inner Bangkok are lower risk than rural or island areas. DEET-based or picaridin repellent is worth applying daily, especially around dusk. Many modern Thai apartments come with screens and air conditioning, both of which help enormously — mosquitoes don’t love cold air. If you’re in budget accommodation without screens, a mosquito net is a worthwhile investment. For details on what apartments typically include, see our Chiang Mai renting guide.

Ants are persistent and organized. Leave a crumb trail on the counter and you’ll have a visitor delegation within the hour. The fix is straightforward: keep food in sealed containers (glass or hard plastic — they can get through thin bags), wipe down surfaces after cooking, and don’t leave pet food out overnight. Every 7-Eleven in Thailand sells ant chalk and spray for about 30 baht ($1.20 CAD) if they find their way in.

Cockroaches make occasional appearances, same as in Mexico — tropical climate, outdoor species, not a reflection of your apartment’s cleanliness. Same prevention: sealed food, covered drains, nightly trash routine.

The Gecko Section (Yes, They Deserve Their Own Section)

If you move to Thailand, you’re going to have geckos in your apartment. This is a feature, not a problem.

The small ones — jing-jok (house geckos) — are translucent, maybe 10 centimetres long, and almost silent. They hang out on walls and ceilings, minding their own business and eating mosquitoes, ants, and moths. They don’t bite. They don’t get in your food. They don’t want anything to do with you. Most expats go from “there’s a lizard on my wall” to “that’s just Gerald” within about two weeks.

The larger ones — tokay geckos — are a different experience. They’re bigger (up to 30 centimetres), brightly coloured, and they make a loud “TO-kay, TO-kay” call that you will absolutely hear from bed at night. They’re startling at first. They’re also phenomenal pest control — a single tokay can eat dozens of cockroaches and large insects per week. They stay out of your way and they earn their keep.

Don’t kill geckos. Seriously. They’re doing more for your insect situation than any spray or plug-in device ever will. In Thai culture, house geckos are considered good luck. We’d call them the most effective and least demanding roommate you’ll ever have.

Prevention That Works Everywhere

Regardless of which country you choose, these habits cover about 90% of insect management. None of them are complicated.

  • Check for window screens when apartment hunting. This is the single highest-impact thing you can do. If a rental doesn’t have screens, ask if the landlord will install them — or factor in the cost of adding them yourself (usually $20-60 CAD per window).
  • Use repellent with DEET (20-30%) or picaridin. Apply it in the evening, especially in Mexico and Thailand. Your local pharmacy will carry options, but if you prefer a Canadian brand you trust, bring a bottle from home.
  • Seal your food. Airtight containers for anything open — cereal, rice, snacks, sugar. Ants and cockroaches can’t eat what they can’t reach.
  • Take out trash daily. Especially food waste. In warm climates, yesterday’s dinner scraps are tonight’s insect invitation.
  • Run ceiling fans. Mosquitoes are weak fliers. A ceiling fan on medium speed makes it harder for them to land on you. Many Thai and Mexican apartments come with them — another thing to check during your rental search.
  • Keep drains covered. Cockroaches travel through plumbing. A simple drain cover (under $5 CAD) blocks that entry point.

If you’re coming from a house in Canada where you never thought about bugs, there’s a brief adjustment period — maybe two to three weeks — where you notice every ant and hear every gecko. After about a month, these habits are automatic and insects become background noise. Every long-term expat we’ve spoken to says the same thing: it stops being a thing.

When to See a Doctor

Most insect encounters abroad are the same as in Canada — annoying, itchy, and gone in a few days. But there are a few situations where a clinic visit is the right call.

  • Dengue symptoms: High fever, severe headache, pain behind the eyes, joint and muscle aches, and sometimes a rash — usually 4-10 days after a mosquito bite. Dengue is treatable but needs monitoring. If you have these symptoms in Mexico or Thailand, see a doctor that day. (This is one of the reasons we strongly recommend private health insurance abroad — a dengue-related clinic visit and blood test is straightforward and affordable with coverage.)
  • Bites that don’t heal: If a bite is still swollen or worsening after 3-4 days, or shows signs of infection (red streaking, pus, warm to the touch), get it checked. Tropical climates can slow healing and increase infection risk from scratching.
  • Allergic reactions: Difficulty breathing, significant swelling beyond the bite area, dizziness, or hives after an insect bite — go to a clinic or hospital immediately. This is the same advice your doctor would give you in Canada.
  • Scorpion stings: Most are just painful, but if you experience numbness, muscle twitching, difficulty breathing, or the sting is on a child — seek medical attention right away.

A travel health clinic in Canada can advise on any vaccinations or medications recommended for your specific destination before you leave. Book that appointment — it’s one of those pre-departure boxes that’s genuinely worth checking. We cover more of these in our packing and pre-departure guide.

What to Pack for Bug Management

You don’t need a suitcase full of insect gear. A few items from home, and you’ll pick up the rest locally for less.

  • DEET or picaridin repellent (travel size). Bring one bottle from Canada that you know works for you. You can buy refills locally in all three countries, but having a familiar product for your first week takes one thing off the adjustment list. A good Canadian option runs about $10-15 CAD at any pharmacy.
  • A lightweight mosquito net. Only necessary if you’re staying in budget accommodation without screens or air conditioning — mainly relevant in Thailand. A compact travel net runs $25-40 CAD and packs down to the size of a water bottle. If your apartment has screens and AC, you won’t need it.
  • Antihistamine cream. For bites that swell or itch persistently. Hydrocortisone cream (available over the counter) and oral antihistamines like cetirizine handle most reactions. Bring a tube from home; buy more locally when it runs out.
  • A few airtight food containers. Not essential to bring from Canada — you’ll find them at any local supermarket or home store — but if you have favourites, toss a couple in your checked luggage.

Everything else — ant spray, plug-in repellent devices, drain covers — is cheaper and easier to buy locally. A trip to a pharmacy and a hardware store in your first week covers it for under $15 CAD total.

The Adjustment Is Real (and It Passes)

We won’t pretend there’s no adjustment. The first time you see a cockroach the size of your thumb, or hear a tokay gecko at midnight, or discover an ant highway across your kitchen counter — there’s a moment. It’s new, it’s unfamiliar, and if you’re from a colder climate where insects mostly disappear for half the year, it can feel like a lot.

But here’s what every long-term expat in all three countries tells us: it takes about two to three weeks to stop noticing, and about a month to stop caring entirely. The habits become automatic. The geckos become familiar. The occasional cockroach becomes exactly that — occasional.

Canada has blackflies that draw blood, deer ticks carrying Lyme disease, wasps that nest in your eaves, and mosquitoes thick enough to hear from inside the house in Northern Ontario. Every climate has its insects. These are just different ones, and once you know the strategies, they’re no harder to manage than the ones you grew up with.

The tradeoff for a few new bugs? Morning coffee on a terrace in Mérida, a $5 pad thai in Chiang Mai, or a glass of wine overlooking the Douro in Porto. Most people find it’s a trade worth making.

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All prices in CAD. Health information is general — consult a travel health clinic for advice specific to your destination and medical history. Insect activity varies by season, neighbourhood, and accommodation type.

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