The Salar de Uyuni is the largest salt flat on earth, about 10,500 square kilometres of salt crust in southwest Bolivia, sitting at roughly 3,656 meters above sea level. It is the flattest place on the planet, varying by less than a meter across its entire width, which is why satellites use it for calibration.

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It is also one of the more physically demanding destinations in this guide, and not because of walking. Four things make packing for Uyuni unlike anywhere else.

The altitude. 3,656 meters on the salar, and standard three-day tours climb above 4,800 meters. Altitude sickness is the most common reason trips go wrong here.

The temperature range. Daytime can reach 20 degrees in full sun and nights on the altiplano drop to minus 10 or lower in winter. That is a 30 degree swing in twelve hours.

The sun. At this altitude with a white reflective surface below you, UV is extreme and comes from below as well as above. People burn the underside of their chin and inside their nose.

The salt. It gets into everything and it corrodes. Boots, camera gear, zips and vehicle undersides all suffer.

Altitude: Acclimatise First

This is the most important thing on the page.

Uyuni town sits at 3,656 meters. The standard three-day tour to the Bolivian border with Chile climbs to around 4,850 meters at the Sol de Mañana geysers and sleeps at roughly 4,200 to 4,500. Flying straight into Uyuni from sea level and starting a tour the next morning is how people end up unwell in a jeep eight hours from a clinic.

Spend at least two nights at altitude before you start. La Paz is 3,600 meters, Sucre is 2,750, and Potosí is 4,090. Most people arrive from La Paz, which acclimatises you adequately if you have already spent a couple of days there. Coming up from San Pedro de Atacama in Chile at 2,400 meters is a sharper jump.

Practical measures: drink far more water than feels necessary, eat lightly, avoid alcohol for the first day or two, and take it slowly. Coca tea is offered everywhere and genuinely helps. Acetazolamide is worth discussing with a travel doctor before you leave.

Know the warning signs. Headache, nausea and breathlessness are common and usually manageable. Confusion, an inability to walk straight, or breathlessness at rest are serious and mean descending immediately. Tour operators carry oxygen, and you should confirm that yours does before booking.

Recommended Tours and Experiences

Wet Season or Dry Season

These are two completely different experiences and you should choose deliberately.

Wet season, December through April: the mirror

Rain leaves a thin layer of water across the salt, and because the surface is almost perfectly level it forms a continuous mirror to the horizon. The sky reflects completely, the line between ground and air disappears, and it is genuinely one of the strangest visual experiences available anywhere. This is the effect in every famous photograph.

The trade-offs are real. Water depth varies, and when it is too deep, parts of the salar become inaccessible, including Incahuasi island. Some multi-day routes are curtailed. Cloud is more frequent, which matters for stargazing. And February is the wettest month, with the best mirror and the most disruption.

The sweet spot is usually late January through March, when there is enough water for reflections and not so much that the tours change.

Dry season, May through November: the hexagons

The salt dries into a crust of polygonal tiles stretching to the horizon, which is the other iconic image. The whole salar is drivable, Incahuasi island with its giant cacti is accessible, the perspective photographs that rely on a flat dry surface work, and the night skies are the clearest in the world.

The cost is cold. June through August are the coldest months, with night temperatures on the altiplano regularly reaching minus 15 to minus 20. Accommodation on the three-day route is basic and often unheated.

Three Merino Base Layers

This is a genuine recommendation rather than an upsell, and Uyuni is one of the few places where three is the right number.

The Roman Trail Women's Merino Wool Base Layer ($49-59) is the foundation, and here is why you want three of them.

On a three-day tour you are in a 4x4 with five other people, you sleep in a basic refugio or a salt hotel, and there is no laundry and often no shower. Water is scarce and heating is minimal. You will sleep in your base layer because the rooms are cold, wear it all the next day, and repeat.

Merino is the one fibre that stays acceptable through that. It also handles the day's 30 degree swing better than anything else: alone in the sun at midday, layered under a fleece and a down jacket for a 5am geyser stop at minus 10. Two get you through; three means one is always clean and dry, which after two nights at 4,300 meters matters more than it sounds.

The Rest of the Layering System

Mid Layer

The Columbia Women's Fast Trek II Jacket ($65), worn most of every day and slept in on the coldest nights.

Insulated Layer

The Columbia Women's Powder Lite II Hooded Jacket ($115) is not optional in any season. Sunrise on the salar and the Sol de Mañana geysers at 4,850 meters before dawn are the two coldest moments, and both are the highlights of the trip.

Wind Shell

The Marmot Women's PreCip Eco Rain Jacket ($110). Rain matters in the wet season, but the real job is wind: the altiplano is entirely exposed and wind chill at 4,500 meters is the thing that makes it unbearable rather than merely cold.

Footwear, and the Salt Problem

Salt is corrosive and it wicks into leather, stitching and metal. Boots that go onto the wet salar come back stained, stiffened and salt-crusted, and repeated exposure damages them permanently.

Two approaches. Either bring the Merrell Women's Moab 3 Waterproof Hiking Boot ($140) and accept it will need a thorough freshwater rinse and dry immediately afterwards, which usually saves them. Or bring cheap rubber boots, which many operators supply for wet-season tours and which are the sensible option if the water is deep.

Rinse everything in fresh water the same day. Boots, tripod legs, camera bag, trouser hems. Salt left to dry keeps working.

Waterproof is essential in the wet season, because you will be standing in a few centimetres of brine to get the photographs.

For socks, the Darn Tough Women's Hiker Micro Crew Merino Socks ($28), four pairs. Cold feet at altitude are miserable and merino keeps working damp.

Sun Protection at 3,656 Meters

This is underestimated more than the cold.

UV intensity rises roughly 10 percent per 1,000 meters of altitude, and the salt flat reflects most of what hits it straight back up. You are being burned from two directions at once.

What that means: high-factor sunscreen applied to the underside of your chin, your nostrils and your ears, which people forget entirely. Reapply every two hours. Category 3 or 4 sunglasses, ideally wraparound, because snow-blindness style eye damage is a genuine risk on the white surface. A wide-brimmed hat. And long sleeves, which is the other argument for merino: it covers you without overheating.

Lip balm with SPF is not optional. Cracked lips at altitude in dry cold are the most common minor complaint on these tours.

What Else Goes In the Bag

A power bank. Refugios have limited generator electricity for a few hours in the evening, and cold drains batteries fast.

Spare camera batteries, kept in an inside pocket against your body. Cold flattens them quickly.

A headtorch for the 4am starts and unlit accommodation.

A sleeping bag liner or a warm sleeping bag if your operator does not supply proper bedding. Ask.

Toilet paper and hand sanitiser. Facilities on the route are basic and often charge a few bolivianos.

Snacks and plenty of water, ideally a filter bottle, since you cannot rely on refill points.

Cash in bolivianos. Uyuni has ATMs that run empty and card acceptance is limited. Bring enough for the whole tour plus extra.

A dry bag for camera gear against salt and damp.

Uyuni Packing FAQ

How do I get there? Flights from La Paz to Uyuni take under an hour. The overnight bus from La Paz takes ten to twelve hours and the newer cama services are reasonably comfortable. Many people arrive from or continue to San Pedro de Atacama in Chile, which the three-day tour connects to.

Is Uyuni safe for solo women? Reasonably, within the tour structure. You are in a shared 4x4 with a driver-guide and other travellers throughout. Uyuni town itself is small and unremarkable. The real risks are altitude, cold and road safety rather than crime: choose an operator on safety record rather than price, since there have been serious accidents involving fatigued drivers and poorly maintained vehicles on these routes. Ask about vehicle age, whether they carry oxygen, and whether the driver does the whole three days alone.

What is the three-day tour? The standard route runs Uyuni to the salar, then south through the Siloli desert, Laguna Colorada with its flamingos, the Sol de Mañana geysers at 4,850 meters, and Laguna Verde beneath Licancabur volcano, finishing either back in Uyuni or at the Chilean border for San Pedro de Atacama.

Can I drink the tap water? No. Bottled or filtered throughout Bolivia.

What should I eat? Tour food is simple and repetitive. In Uyuni town, try salteñas, the baked Bolivian empanada eaten mid-morning, and llama steak, which is lean and good. Coca tea constantly.

The Short Version

Three merino base layers, a fleece, an insulated hooded jacket, a windproof shell, waterproof boots you are prepared to rinse or cheap rubber boots, four pairs of merino socks, hat, gloves, a neck gaiter, category 3 or 4 sunglasses, high-factor sunscreen for the underside of your chin, SPF lip balm, a headtorch, a power bank, spare batteries, toilet paper, a filter bottle and cash in bolivianos.

Acclimatise for two nights before you start. Rinse the salt off the same day. Choose the wet season for the mirror and the dry season for the hexagons and the stars.

You can read more about building a merino-first travel wardrobe on the Roman Trail merino wool base layer guide, and there is a full Bolivia travel guide for women plus guides to Peru and Chile, both common continuations. Browse the full collection at Roman Trail women's merino base layers.

If the outer journey is calling you, the inner one usually is too. Explore SoulMap at romantrail.com/blogs/soulmap.