Mosquitoes, dengue and chikungunya in Réunion

What the mosquito risk actually looks like on the ground

I get asked about this more than almost anything else, usually a few weeks before someone flies in: is Réunion Island dangerous because of mosquitoes? The honest answer is neither yes nor no. Réunion has had real dengue epidemics in recent years, and chikungunya has circulated too, so this isn’t a theoretical warning I’m adding for the sake of completeness. At the same time, most visitors who spend a week or two here, follow a few basic habits and don’t end up thinking about it again after the first couple of evenings. This isn’t a reason to cancel a trip. It’s a reason to pack repellent and plan your evenings a little differently than you would in the Alps. If you’re weighing this alongside the island’s other practical concerns, it’s worth reading the broader answer to is Réunion Island safe for tourists rather than treating mosquitoes as the whole picture.

Dengue and chikungunya are both spread by the same mosquito, active mainly at dawn and dusk, and both have caused documented outbreaks on the island in recent seasons, with case numbers rising and falling year to year depending on rainfall and standing water. Local health authorities track this closely and issue public updates when activity picks up, so if you want the current situation rather than a general statement, checking before you travel is worth the five minutes. It’s a good idea to fold this into the same research pass as entry requirements for Réunion Island, since both are the kind of practical checks best done before you book rather than after you land.

Why the hot, wet season matters here

Réunion runs on southern hemisphere seasons, which trips up a lot of first-time visitors. The austral summer, from roughly November to April, is hot and humid, and it’s also when mosquito activity climbs, simply because standing water after tropical rain gives them more places to breed. The austral winter, May to October, is drier and cooler, especially in the highlands, and mosquito presence generally drops with it. None of this means the winter months are risk-free or that summer is off-limits. It means the precautions I’d tell a friend to take matter more if you’re visiting between November and April, particularly on the humid east coast around Saint-Benoît and Sainte-Rose, where rainfall is heaviest. For the month-by-month detail, see Réunion Island weather by month and, if you’re weighing the trade-offs of visiting in the hot season, the best time to visit Réunion Island.

The austral summer is also the island’s cyclone season, which is worth reading alongside the mosquito advice rather than separately, since both push toward the same conclusion: the drier winter months make for an easier trip on several fronts at once, not just hiking access to the Piton de la Fournaise and the cirques. If you’re specifically comparing conditions on the wetter east coast against the drier west coast, the mosquito risk tracks the same rainfall pattern: higher around Saint-Benoît and Sainte-Rose, lower around Saint-Gilles-les-Bains and Saint-Leu.

What actually reduces the risk

The advice here isn’t complicated, and it’s the same advice I follow myself when I’m out on the east coast or staying somewhere without air conditioning. Repellent on exposed skin in the early morning and again from late afternoon into the evening, since that’s when the mosquitoes that carry dengue and chikungunya are most active. Long sleeves and long trousers at dusk, especially if you’re sitting outside for dinner, which in Réunion is a genuine pleasure I wouldn’t want anyone to skip out of nervousness. If your accommodation has screens or a mosquito net, use them; if it doesn’t and you’re staying somewhere rural, it’s worth asking about one when you book. This is exactly the kind of detail I’d want covered before departure, so it sits well alongside the fuller what to pack for Réunion Island checklist and the general travel mistakes to avoid in Réunion Island.

If you’re staying in a gîte deep in Mafate, where there’s no road and no car, or working through the wider hiking in Mafate planning guide, it’s worth asking your host about screens in advance rather than assuming every gîte has them, since standards vary more in the cirques than on the coast.

None of this should stop you getting out on the water or into the air. A morning boat trip along the west coast lagoon, for instance the dolphin and whale watching excursion out of Saint-Gilles-les-Bains, puts you offshore in the breeze, which is about as low-risk a setting as the island offers. The same goes for anything airborne: a tandem paragliding flight above the bay of Saint-Leu or a slow pass over the lagoon on an ULM flight over the Hermitage and La Saline-les-Bains lagoon keeps you well clear of the vegetation and standing water where mosquitoes gather. I mention these not to sell you on them but because they’re a genuinely easy way to enjoy a full day here without spending it worrying about your ankles.

The same logic applies to water time closer to shore: snorkelling and kayaking in the Hermitage lagoon or a session covered in the things to do in Saint-Gilles guide keeps you out over open water rather than near the vegetation where mosquitoes gather during the day.

Don’t confuse this with the leptospirosis warning

This is where I see people mix up two separate pieces of advice, so I want to be direct about it. The mosquito risk, dengue and chikungunya, is about insect bites, mainly at dawn and dusk, anywhere on the island. Leptospirosis is a completely different hazard, spread through freshwater contaminated by animal urine, and the relevant advice is to avoid swimming or wading in rivers, streams and natural pools after heavy rain, when runoff carries the bacteria into the water. One is about covering your skin in the evening; the other is about which water you swim in and when.

Conflating the two leads to either underestimating one risk or worrying about the wrong thing at the wrong moment, and I’d rather you carry both pieces of advice clearly than blend them into one vague “watch out for bugs and water” warning. For the sea-water side of the same question, is it safe to swim in Réunion: sharks and beaches covers the separate set of rules that apply along the coast, and can you drink tap water in Réunion Island rounds out the water-related practicalities.

What I actually pack and do

On a practical level, here’s what I bring on every trip: a DEET-based or picaridin-based repellent bought before I travel, since pharmacy stock on the island varies; a lightweight long-sleeve layer I can put on around 5pm without overheating; and, if I’m staying in a gîte in the Cirques or somewhere without screens, a portable mosquito net. I also keep an eye on ankles and wrists specifically, since that’s where most bites land when you’re wearing shorts during the day. If you develop a fever, joint pain or a rash within a couple of weeks of a trip, mention Réunion to a doctor, since dengue and chikungunya symptoms can overlap with other illnesses and the travel history helps with diagnosis.

None of this is meant to dramatize the risk. Most travellers who take the basic precautions have an uneventful trip on that front, and the island’s real logistical challenges, mountain driving times, weather-dependent volcano access, tend to matter far more day to day than mosquitoes do. Those logistics, and how much a trip actually costs once you’ve budgeted for repellent, a rental car and everything else, are covered in Réunion Island trip cost and driving in Réunion Island. But dengue and chikungunya are real, documented, and worth a genuinely honest answer rather than either a scare story or a dismissive shrug. If you’re travelling with family, the same precautions apply and are folded into Réunion Island with kids and the matching five-day itinerary for families.

Mosquitoes, dengue and chikungunya: frequently asked questions

Is the mosquito risk in Réunion Island serious?

There have been real dengue and chikungunya outbreaks on the island in recent years, so the risk is genuine, not hypothetical. It’s manageable with repellent and covering up at dawn and dusk, and it shouldn’t be confused with a reason to avoid the island altogether.

When is the mosquito risk highest in Réunion?

Mosquito activity tends to rise during the hot, humid austral summer, roughly November to April, when rainfall creates more standing water for breeding. The drier austral winter, May to October, generally sees lower activity, though basic precautions are worth keeping year-round.

What’s the difference between the dengue risk and the leptospirosis risk?

Dengue and chikungunya are spread by mosquito bites, mainly at dawn and dusk, anywhere on the island. Leptospirosis is spread through freshwater contaminated by animal urine, and the relevant precaution is avoiding rivers and natural pools after heavy rain, not insect repellent.

What repellent should I bring to Réunion?

A DEET-based or picaridin-based repellent bought before you travel is a safe bet, since availability in local pharmacies can vary. Apply it on exposed skin in the early morning and again from late afternoon through the evening.

Do I need a mosquito net in Réunion?

Most coastal hotels and guesthouses have screens or air conditioning, which covers most of the risk. If you’re staying in a rural gîte, particularly in the Cirques, it’s worth asking whether one is provided or packing a lightweight portable net.

Can I still do outdoor activities if I’m worried about mosquitoes?

Yes. Activities on the water or in the air, such as a boat trip along the lagoon or a paragliding flight over Saint-Leu, keep you away from the vegetation and standing water where mosquitoes gather, and are a low-risk way to spend a full day outdoors.

Should I see a doctor after my trip if I feel unwell?

If you develop a fever, joint pain or a rash within a couple of weeks of returning from Réunion, mention your travel history to a doctor. Dengue and chikungunya symptoms can resemble other illnesses, and that detail helps with diagnosis.

Does the mosquito risk affect whether Réunion is safe to visit?

It’s one practical factor among several, alongside mountain driving times and weather-dependent hikes, rather than a reason to avoid the island. Basic precautions, repellent and covering up at dusk, address most of the risk for a typical one- or two-week trip.