If you have ever been parked beside a quiet river with a mug of tea, enjoying the stillness, only to be repeatedly dive-bombed by a loud, determined fly, there is a good chance you have crossed paths with a horse fly. They look fairly ordinary at first glance, but the bite tells a different story. Painful, sharp, and delivered with impressive commitment, they have a way of interrupting an otherwise calm wild camping evening.
After years of living and travelling in a campervan, I have had more encounters with horse flies than I would like. Enough, at least, to learn how they behave, where they turn up, and what actually helps when they do. This is a grounded look at what they are, why they bite, and how to deal with them while travelling.
What a horse fly actually is
Horse flies, known as clegs in parts of the UK, are large, aggressive flies commonly found near water, woodland, and open fields. Unfortunately, that also describes many of the places we enjoy parking up. They are usually between 1 and 2.5 centimetres long, with dark, solid bodies and large eyes that can appear metallic or patterned in certain light. Compared to a house fly, they feel heavier, tougher, and far more purposeful.
They are quick, persistent, and not easily scared off. Once one has decided you are interesting, it tends to stick with you.
How to recognise a horse fly:
- Noticeably larger than a standard fly
- Prominent eyes, often patterned or metallic
- Clear or slightly smoky wings
- Persistent behaviour, hovering, circling, and repeatedly returning
Why horse flies bite
Only female horse flies bite. They are not doing it out of aggression. They need blood to develop their eggs.
Unlike mosquitoes, which pierce the skin, horse flies use scissor-like mouthparts to slice it open. That is why the bite hurts straight away and often swells more than you expect. They are not selective either. Horses, cattle, dogs, and humans are all fair game.
Put simply:
- Male horse flies feed on nectar and plant matter
- Female horse flies need blood to reproduce
- You attract them because you are warm, moving, and nearby
Where and when you are most likely to encounter them
Horse flies are mainly active in warm weather, particularly between June and August. They thrive in places with moisture and animal activity, including:
- Wetlands and marshes
- Lakes, rivers, and streams
- Woodland edges and clearings
- Fields with grazing livestock
From a vanlife point of view, this often means they appear when you are:
- Parked near water for a swim
- Wild camping in lush countryside
- Walking or hiking in rural areas
- Sitting outside the van in the late afternoon
They are daytime insects and are especially active on hot, still, humid days. Wind makes a noticeable difference. Even a light breeze can discourage them, as they are not strong fliers.
What a bite is like
Reactions vary from person to person. Some barely notice more than a sore spot, while others are left with swollen, itchy welts that last several days.
Common symptoms include:
- Immediate sharp pain, similar to a sting
- A red, raised bump or blister
- Itching or burning
- Swelling around the area
In rare cases, bites can become infected or trigger an allergic reaction, so they are worth keeping an eye on, especially when you are travelling off-grid.
Preventing horse fly bites on the road
Most prevention comes down to choosing your spot carefully and being realistic about conditions.
Avoid problem areas
If a place feels damp, still, and full of livestock, it is often worth moving on. Higher ground or breezier spots usually mean fewer flies.
Cover exposed skin
Loose-fitting clothing that covers arms and legs helps more than you might expect. Light colours are better, as horse flies are attracted to dark shades and shiny skin.
Use a suitable repellent
Standard mosquito repellents do not always work well. Products containing DEET, picaridin, or oil of lemon eucalyptus tend to be more effective, though stronger formulas are often needed.
Use the wind to your advantage
Parking where there is airflow can make a big difference. Hills, coastal spots, or simply facing into the breeze can reduce fly activity.
Fit mesh screens
Door and window screens are one of the best van upgrades for summer. They allow ventilation while keeping insects out. If you sit outside often, a small net canopy can also help.
Natural deterrents
Some people have partial success with natural options such as lavender, citronella, or eucalyptus oils, clove-studded lemons placed nearby, or burning herbs like sage or rosemary. Results vary, but they can help when combined with other measures.
If you do get bitten
Even with care, bites still happen.
Start by cleaning the area with soap and water. A cold compress helps reduce swelling, and antihistamine creams or tablets can ease itching. Try not to scratch, especially if you are travelling without easy access to washing facilities.
Seek medical advice if the bite becomes very swollen, hot, or infected, if you feel unwell, or if swelling occurs near the eyes, lips, or throat.
Lessons learned from van life
A few practical habits make life easier:
- Close van doors quickly. Horse flies are bold and will happily follow you inside.
- Camp higher when possible. Above around 300 metres, they tend to be less common.
- Keep a basic bite kit on board with antiseptic wipes and antihistamine cream.
- Expect more flies near animals. Livestock attract them first, but humans are an easy second option.
They are frustrating, but predictable once you start noticing patterns.
Final thoughts
Horse flies are an unwelcome part of summer travel in the countryside, but they do not need to derail your plans. With a bit of awareness and some simple adjustments, it is usually possible to stay comfortable and avoid the worst of them.
Like many aspects of van life, it comes down to adapting as you go. Over time, you start recognising the conditions they like, and avoiding them becomes second nature.
And if nothing else, they are a reminder that even the quietest park-ups come with their own small challenges.