La Sportiva Nucleo High II GTX Review: The Waterproof Boot That Breathes
A Field Report from the Jungle Trails of Pavones
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Most waterproof boots make you a deal: dry feet, but you'll cook. Wrap a foot in leather and a membrane, walk it into tropical humidity, and by noon you're wearing a swamp you can't take off.
Not this one.
The La Sportiva Nucleo High II GTX is built around a different idea: a waterproof boot that breathes out the sides and through the sole. Nubuck leather. GORE-TEX Surround. A sticky Vibram outsole. Just over a pound per boot. On paper, that's a combination that shouldn't hold up in a rainforest as well as it does.
I found out in Pavones. On our last day there, Uncle Michael took us to Punta Banco. We cut across the beach, clambering over fallen palm trees while the waves crashed around us, then followed a path marked by stones the size of my head into dense jungle, grabbing ropes where the trail got steep, until the sound of rushing water turned into a waterfall. That day, we found two more.
Three waterfalls in one day. My feet stayed dry — the only water that ever got in came over the top of the collar.
Why I Bought It — and Why the Nucleo
For years, my travel boot was a pair of Timberland Redwood Falls. They're in my 2024 travel essentials for good reason: comfortable, waterproof, handsome enough for treks through the Tuscan countryside and pasta dinners in Italian villas. But a handsome travel boot has a ceiling, and a rainy-season expedition into the jungle above the Golfo Dulce sits well above it.
So I went to a specialist. La Sportiva has been building technical mountain footwear since 1928, and the Nucleo High II GTX is their answer to a specific problem: how do you make a waterproof leather boot that doesn't turn into a sauna? A nubuck leather upper with Nano-Cell vents. A GORE-TEX Surround membrane. A Vibram Nano XS-Trek outsole with La Sportiva's Impact Brake System. 16.8 ounces per boot. $259.
Mine are Carbon/Forest. See the Nucleo High II GTX at Backcountry →
First Impressions vs. On the Road
Out of the box, they look like a classic leather hiker and feel lighter than they look. What they don't feel is broken in. The Nucleos took a while to settle — so give yourself time with them before the trip that matters, not during it.
Then came the real test, and it started before we ever saw a trail: a 3 a.m. start in Pittsburgh, a connection in Houston to meet up with Spencer and Wynn, a flight into San José, and a drive out to Dominical. Almost twenty hours of airports, cramped seats, and car rides. Boots the whole way. My feet were comfortable all day.
Day one, they were stiff. By day ten, they'd earned their spot.
The Membrane Question: Does GORE-TEX Surround Actually Breathe?
Here's the problem with most waterproof boots: the membrane keeps water out, but traps the sweat. Your foot has nowhere to vent but up and out of the collar. GORE-TEX Surround attacks that from below. Nano-Cell inserts in the leather and a spacer layer under the footbed let heat and moisture escape the sides and through the sole — what Backcountry calls 360° breathability.
That's the claim. Costa Rica in June was the test: rainy season, the air already saturated before the first drop falls, heat that doesn't quit after sundown. Most reviews put this boot through spring thaw and mountain trails out West. Very few put it through the tropics.
Here's my verdict: they breathed. On jungle trails and across nearly twenty hours of travel, my feet were comfortable all day. And they stayed dry — the only water that ever got in came over the top. That's not a membrane failure. That's a boot that's only so tall.
Waterproof and breathable, in the place that tests both at once.
Traction: The Vibram in Red Mud
La Sportiva's roots are in climbing, and you can feel it underfoot. The Vibram Nano XS-Trek outsole runs deep lugs, and the Impact Brake System angles them so more rubber bites on the way down.
The jungle above Pavones is a traction gauntlet. On our first afternoon at the farm, Uncle Michael and Gus the farm dog led us down the waterfall trail to find a howler monkey hanging from a bejuco vine — red mud, slick roots, leaf litter hiding whatever's underneath. On the last day, it was Punta Banco's path of wet, head-sized stones.
The Nucleos stuck to all of it. Red mud, roots, wet rock — I never had a slip worth mentioning.
The Ankle and the Small Stuff
The "High" is real: an over-the-ankle cut with a 3D Flex hinge, so it supports without locking you into a cast. Inside, an Ortholite Hybrid insole over a compression-molded EVA midsole. The outsole is resoleable, which matters on a $259 boot you intend to keep, and La Sportiva builds it without intentionally added PFAS.
Two things worth knowing before you order: La Sportiva recommends sizing up a half size from your street shoe, and reviewers consistently say it runs narrow. A Wide version exists for exactly that reason. Some reviews also grumble about the laces. I haven't had trouble with mine.
Travel Performance
On this trip, I wore the Nucleos on every travel day: Pittsburgh to Houston to San José, the drive down to Dominical, three hours through palm rows and downpours to Pavones, and the same road in reverse at the end. Wearing the heaviest thing on your packing list is the oldest one-bag trick — everything else rode in my Aer Travel Pack 4 Ultra. (The Long Way In is where that trip starts.)
In between, they were my day-trip shoes too — runs into Pavones for snacks at Supermercado Rio Claro, and an evening at Pavones Point watching surfers take on double-overhead waves.
The one honest caveat: off the trail, they read as hiking boots. Good-looking ones — but for cobblestones and a nice dinner, that's still the Timberlands' job.
The Downsides (Real Talk)
No boot is perfect. Here's what to know.
The break-in. It took a while. Put miles on them before the trip, not during it.
The collar is the limit. The membrane held; water only got in over the top. Go deep enough, and every boot fills.
Fit. Size up a half, per La Sportiva, and try them on if you can — it runs narrow.
Price. $259 is real money. You're paying for the membrane, the rubber, and a sole you can rebuild.
Who It's For
Hikers in hot, wet climates who gave up on waterproof boots because they cook
Travelers who want one boot for the plane, the trail, and the day trip
Anyone on muddy, rooty, or wet-rock terrain who wants real traction
People who'd rather resole a boot than replace it
Who Should Skip It
Wide feet — try the Wide version, or try before you buy
Anyone who needs a boot that's ready on day one — the break-in is real
City-first travelers — a classic leather boot like the Redwood Falls is the better look for cobblestones and dinner
The Verdict
The Gear Spotlight test is always the same: if these boots disappeared tomorrow, would I buy them again?
Yes — absolutely.
And the question readers of my 2024 travel essentials will actually ask: Nucleos or Redwood Falls?
Easy. The Timberlands are for cobblestones and city dinners. The Nucleos are for everything wild — the jungle, the waterfall, and the twenty-hour travel day that gets you there. Two different boots with two jobs. No overlap.
The crew: Spencer (@spencer.is.a.story), Wynn (@wy_photo_video), with Uncle Michael leading the way to the waterfalls. Everyone credited, every time.
Siempre una aventura.
Product images courtesy of La Sportiva via Backcountry. Field testing conducted during a June 2026 Creator Expedition to Pavones, Costa Rica. This post contains affiliate links; The Modern Xplorer may earn a commission on purchases at no extra cost to you.
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